[FACE OF NOTE]

                                  ICG HOLDINGS, INC.

                        11 5/8% Senior Discount Note Due 2007

                                                  [CUSIP] [CINS] __________


          No.                                                    $_________

                    The following information is supplied for purposes of
          Sections 1273 and 1275 of the Internal Revenue Code:

          Issue Date:    March 11, 1997      Original issue discount under
                                             Section 1273 of the Internal
          Yield to maturity for period       Revenue Code (for each $1,000
          from Issue Date to March 15,       principal amount at maturity): 
          2007:  11.62% (rounded to two       $1,013.59
          decimal places), compounded
          semiannually on March 15 and       Issue Price (for each $1,000
          September 15 commencing            principal amount at maturity): 
          March 11, 1997 (computed           $567.66
          without giving effect to the
          additional payments of
          interest in the event the
          issuer fails to commence the
          exchange offer and fails to
          cause the shelf registration
          statement to be declared
          effective, each as referred to
          on the reverse hereof)

                    ICG HOLDINGS, INC., a Colorado corporation (the
          "Company", which term includes any successor under the Indenture
          hereinafter referred to), for value received, promises to pay to
          [____________], or its registered assigns, the principal sum of
          [_____] ($[_____]) on March 15, 2007.

                    Interest Payment Dates:  March 15 and September 15,
          commencing September 15, 2002.

                    Regular Record Dates:  March 1 and September 1.

                   Reference is hereby made to the further provisions of
          this Note set forth on the reverse hereof, which further
          provisions shall for all purposes have the same effect as if set
          forth at this place.

                   IN WITNESS WHEREOF, the Company has caused this Note to
          be signed manually or by facsimile by its duly authorized
          officers.


          Date:  [_______________]          ICG HOLDINGS, INC.


                                            By:                             
                                               -----------------------------
                                               Name:
                                               Title:

          Attest:                             
                 -----------------------------
                Name:
                Title:



                   (Form of Trustee's Certificate of Authentication)

          This is one of the 11 5/8% Senior Discount Notes due 2007
          described in the within-mentioned Indenture.


                                            NORWEST BANK COLORADO,
                                            NATIONAL ASSOCIATION, as Trustee


                                            By:                             
                                               -----------------------------
                                                     Authorized Signatory

          

                                [REVERSE SIDE OF NOTE]

                                  ICG HOLDINGS, INC.

                         11 5/8% Senior Discount Note due 2007     


          1.   Principal and Interest.
               ----------------------

                    The Company will pay the principal of this 11 5/8%
          Senior Discount Note due 2007 (the "Note") on March 15, 2007.

                    The Company promises to pay interest on the principal
          amount of this Note on each Interest Payment Date, as set forth
          below, at the rate per annum shown above.

                    Interest will be payable semiannually (to the holders of
          record of the Notes at the close of business on the March 1 or
          September 1 immediately preceding the Interest Payment Date) on
          each Interest Payment Date, commencing September 15, 2002;
          provided that no interest shall accrue on the principal amount of
          this Note prior to March 15, 2002 and no interest shall be paid on
          this Note prior to September 15, 2002, except as provided in the
          next paragraph.

                    If an exchange offer registered under the Securities Act
          is not consummated, and a shelf registration statement under the
          Securities Act with respect to resales of the Notes is not
          declared effective by the Commission, on or before September 11,
          1997 in accordance with the terms of the Registration Rights
          Agreement dated March 11, 1997 among the Company, the Guarantor
          and Morgan Stanley & Co. Incorporated, interest (in addition to
          the accrual of original discount during the period ending
          March 15, 2002 and in addition to the interest otherwise due on
          the Notes after such date) will accrue, at an annual rate of 0.5%
          of the Accreted Value on the preceding Semi-Annual Accrual Date on
          the Notes, from September 11, 1997, payable in cash semiannually,
          in arrears, on each March 15 and September 15, commencing
          March 15, 1998.  The Holder of this Note is entitled to the
          benefits of such Registration Rights Agreement.

                    From and after March 15, 2002, interest on the Notes
          will accrue from the most recent date to which interest has been
          paid or, if no interest has been paid, from March 15, 2002;
          provided that, if there is no existing default in the payment of
          interest and this Note is authenticated between a Regular Record
          Date referred to on the face hereof and the next succeeding
          Interest Payment Date, interest shall accrue from such Interest
          Payment Date.  Interest will be computed on the basis of a 360-day
          year of twelve 30-day months.

                    The Company shall pay interest on overdue principal and
          premium, if any, and interest on overdue installments of interest,
          to the extent lawful, at a rate per annum that is 2% in excess of
          the rate otherwise payable.

          2.   Method of Payment.
               -----------------

                    The Company will pay principal as provided above and
          interest (except defaulted interest) on the principal amount of
          the Notes as provided above on each March 15 and September 15 to
          the persons who are Holders (as reflected in the Security Register
          at the close of business on such March 1 and September 1,
          immediately preceding the Interest Payment Date), in each case,
          even if the Note is cancelled on registration of transfer or
          registration of exchange after such record date; provided that,
          with respect to the payment of principal, the Company will not
          make payment to the Holder unless this Note is surrendered to a
          Paying Agent.

                    The Company will pay principal, premium, if any, and as
          provided above, interest in money of the United States that at the
          time of payment is legal tender for payment of public and private
          debts.  However, the Company may pay principal, premium, if any,
          and interest by its check payable in such money.  It may mail an
          interest check to a Holder's registered address (as reflected in
          the Security Register).  If a payment date is a date other than a
          Business Day at a place of payment, payment may be made at that
          place on the next succeeding day that is a Business Day and no
          interest shall accrue for the intervening period.

          3.   Paying Agent and Registrar.
               --------------------------

                    Initially, the Trustee will act as authenticating agent,
          Paying Agent and Registrar.  The Company may change any
          authenticating agent, Paying Agent or Registrar without notice. 
          The Company, any Subsidiary or any Affiliate of any of them may
          act as Paying Agent, Registrar or co-Registrar.

          4.   Indenture; Issuance of Additional Notes.
               ---------------------------------------

                    The Company issued the Notes under an Indenture dated as
          of March 11, 1997 (the "Indenture"), among the Company, ICG
          Communications, Inc., a Delaware corporation (the "Guarantor"),
          and Norwest Bank Colorado, National Association, as trustee (the
          "Trustee").  Capitalized terms herein are used as defined in the
          Indenture unless otherwise indicated.  The terms of the Notes
          include those stated in the Indenture and those made part of the
          Indenture by reference to the Trust Indenture Act.  The Notes are
          subject to all such terms, and Holders are referred to the
          Indenture and the Trust Indenture Act for a statement of all such
          terms.  To the extent permitted by applicable law, in the event of
          any inconsistency between the terms of this Note and the terms of
          the Indenture, the terms of the Indenture shall control.

                    The Notes are general unsecured obligations of the
          Company.  The Indenture provides for an initial original issuance
          of an aggregate principal amount at maturity of Notes  of
          $176,000,000, plus any Exchange Securities that may be issued
          pursuant to the Registration Rights Agreement, and, subject to
          Article Four of the Indenture, the issuance from time to time of
          additional Notes under the Indenture.

          5.   Redemption.
               ----------

                    The Notes will be redeemable, at the Company's option,
          in whole or in part, at any time and from time to time on or after
          March 15, 2002 and prior to maturity, upon not less than 30 nor
          more than 60 days' prior notice mailed by first-class mail to each
          Holder's last address as it appears in the Security Register, at
          the following Redemption Prices (expressed in percentages of their
          principal amount at maturity), plus accrued and unpaid interest,
          if any, to the Redemption Date (subject to the right of Holders of
          record on the relevant Regular Record Date that is on or prior to
          the Redemption Date to receive interest due on an Interest Payment
          Date that is on or prior to the Redemption Date) if redeemed
          during the 12-month period commencing on March 15 of the
          applicable year set forth below:

                                                  Redemption
                         Year                         Price    
                         ----                     -------------
                         2002                     105.81250% 
                         2003                     102.90625
                         2004 and thereafter      100.00000

                    In addition, at any time on or prior to March 15, 2000,
          the Company may, at its option from time to time, redeem
          Securities having an aggregate principal amount of up to 35% of
          the aggregate principal amount of all Securities issued, at a
          redemption price equal to 111 5/8% of the Accreted Value thereof
          on the Redemption Date, with proceeds of one or more Public Equity
          Offerings of Common Stock of (A) the Guarantor or (B) the Company,
          provided that (i) with respect to a Public Equity Offering
          referred to in clause (A) above, cash proceeds of such Public
          Equity Offering in an amount sufficient to effect the redemption
          of Securities to be so redeemed are contributed by the Guarantor
          to the Company prior to such redemption and used by the Company to
          effect such redemption and (ii) such redemption occurs within 180
          days after consummation of such Public Equity Offering.

          6.   Notice of Redemption.
               --------------------

                    Notice of any optional redemption will be mailed at
          least 30 days but not more than 60 days before the Redemption Date
          to each Holder of Notes to be redeemed at his last address as it
          appears in the Security Register.  Notes in original denominations
          larger than $1,000 may be redeemed in part.  On and after the
          Redemption Date, interest ceases to accrue on Notes or portions of
          Notes called for redemption, unless the Company defaults in the
          payment of the Redemption Price.

          7.   Repurchase upon Change in Control.
               ---------------------------------

                    Upon the occurrence of any Change of Control, each
          Holder shall have the right to require the repurchase of its Notes
          by the Company in cash pursuant to the offer described in the
          Indenture at a purchase price equal to 101% of the Accreted Value
          thereof plus accrued and unpaid interest, if any, to the date of
          purchase (the "Change of Control Payment").

                    A notice of such Change of Control will be mailed within
          30 days after any Change of Control occurs to each Holder at his
          last address as it appears in the Security Register.  Notes in
          original denominations larger than $1,000 may be sold to the
          Company in part.  On and after the date of the Change of Control
          Payment, interest ceases to accrue on Notes or portions of Notes
          surrendered for purchase by the Company, unless the Company
          defaults in the payment of the Change of Control Payment.

          8.   Denominations; Transfer; Exchange.
               ---------------------------------

                    The Notes are in registered form without coupons in
          denominations of $1,000 of principal amount at maturity and
          multiples of $1,000 in excess thereof.  A Holder may register the
          transfer or exchange of Notes in accordance with the Indenture. 
          The Registrar may require a Holder, among other things, to furnish
          appropriate endorsements and transfer documents and to pay any
          taxes and fees required by law or permitted by the Indenture.  The
          Registrar need not register the transfer or exchange of any Notes
          selected for redemption.  Also, it need not register the transfer
          or exchange of any Notes for a period of 15 days before a
          selection of Notes to be redeemed is made.

          9.   Persons Deemed Owners.
               ---------------------

                    A Holder shall be treated as the owner of a Note for all
          purposes.

          10.  Unclaimed Money.
               ---------------

                    If money for the payment of principal, premium, if any,
          or interest remains unclaimed for two years, the Trustee and the
          Paying Agent will pay the money back to the Company at its
          request.  After that, Holders entitled to the money must look to
          the Company for payment, unless an abandoned property law
          designates another Person, and all liability of the Trustee and
          such Paying Agent with respect to such money shall cease.

          11.  Discharge Prior to Redemption or Maturity.
               -----------------------------------------

                    If the Company or the Guarantor deposits with the
          Trustee money or U.S. Government Obligations sufficient to pay the
          then outstanding principal of, premium, if any, and accrued
          interest on the Notes (a) to redemption or maturity, the Company
          will be discharged from the Indenture and the Notes, except in
          certain circumstances for certain sections thereof, and (b) to the
          Stated Maturity, the Company and the Guarantor will be discharged
          from certain covenants set forth in the Indenture.

          12.  Amendment; Supplement; Waiver.
               -----------------------------

                    Subject to certain exceptions, the Indenture or the
          Notes may be amended or supplemented with the consent of the
          Holders of at least a majority in principal amount at maturity of
          the Notes then outstanding, and any existing default or compliance
          with any provision may be waived with the consent of the Holders
          of at least a majority in principal amount at maturity of the
          Notes then outstanding.  Without notice to or the consent of any
          Holder, the parties thereto may amend or supplement the Indenture
          or the Notes to, among other things, cure any ambiguity, defect or
          inconsistency and make any change that does not materially and
          adversely affect the rights of any Holder.

          13.  Restrictive Covenants.
               ---------------------

                    The Indenture imposes certain limitations on the ability
          of the Company and the Guarantor and its Restricted Subsidiaries,
          among other things, to Incur Indebtedness, make Restricted
          Payments, use the proceeds from Asset Sales, engage in
          transactions with Affiliates or, with respect to each of the
          Company and the Guarantor, merge, consolidate or transfer
          substantially all of its assets.  Within 45 days after the end of
          each fiscal quarter (90 days after the end of the last fiscal
          quarter of each year), the Company must report to the Trustee on
          compliance with such limitations.

          14.  Successor Persons.
               -----------------

                    When a successor person or other entity assumes all the
          obligations of its predecessor under the Notes and the Indenture,
          the predecessor person will be released from those obligations.

          15.  Defaults and Remedies.
               ---------------------

                    The following events constitute "Events of Default"
          under the Indenture:  (a) default in the payment of principal of
          (or premium, if any, on) any Note when the same becomes due and
          payable at maturity, upon acceleration, redemption or otherwise;
          (b) default in the payment of interest on any Note when the same
          becomes due and payable, and such default continues for a period
          of 30 days; (c) the Company or the Guarantor defaults in the
          performance of or breaches any other covenant or agreement of the
          Company or the Guarantor in the Indenture or under the Notes and
          such default or breach continues for a period of 30 consecutive
          days after written notice by the Trustee or the Holders of 25% or
          more in aggregate principal amount at maturity of the Notes; (d)
          there occurs with respect to any issue or issues of Indebtedness
          of the Company, the Guarantor or any Significant Subsidiary having
          an outstanding principal amount at maturity of $10 million or more
          in the aggregate for all such issues of all such Persons, whether
          such Indebtedness now exists or shall hereafter be created, (I) an
          event of default that has caused the holder thereof to declare
          such Indebtedness to be due and payable prior to its Stated
          Maturity and such Indebtedness has not been discharged in full or
          such acceleration has not been rescinded or annulled within 30
          days of such acceleration and/or (II) the failure to make a
          principal payment at the final (but not any interim) fixed
          maturity and such defaulted payment shall not have been made,
          waived or extended within 30 days of such payment default; (e) any
          final judgment or order (not covered by insurance) for the payment
          of money in excess of $10 million in the aggregate for all such
          final judgments or orders against all such Persons (treating any
          deductibles, self-insurance or retention as not so covered) shall
          be rendered against the Company, the Guarantor or any Significant
          Subsidiary and shall not be paid or discharged, and there shall be
          any period of 30 consecutive days following entry of the final
          judgment or order that causes the aggregate amount for all such
          final judgments or orders outstanding and not paid or discharged
          against all such Persons to exceed $10 million during which a stay
          of enforcement of such final judgment or order, by reason of a
          pending appeal or otherwise, shall not be in effect; (f) a court
          having jurisdiction in the premises enters a decree or order for
          (A) relief in respect of the Company, the Guarantor or any
          Significant Subsidiary in an involuntary case under any applicable
          bankruptcy, insolvency or other similar law now or hereafter in
          effect, (B) appointment of a receiver, liquidator, assignee,
          custodian, trustee, sequestrator or similar official of the
          Company, the Guarantor or any Significant Subsidiary or for all or
          substantially all of the property and assets of the Company, the
          Guarantor or any Significant Subsidiary or (C) the winding up or
          liquidation of the affairs of the Company, the Guarantor or any
          Significant Subsidiary and, in each case, such decree or order
          shall remain unstayed and in effect for a period of 30 consecutive
          days; or (g) the Company, the Guarantor or any Significant
          Subsidiary (A) commences a voluntary case under any applicable
          bankruptcy, insolvency or other similar law now or hereafter in
          effect, or consents to the entry of an order for relief in an
          involuntary case under any such law, (B) consents to the
          appointment of or taking possession by a receiver, liquidator,
          assignee, custodian, trustee, sequestrator or similar official of
          the Company, the Guarantor or any Significant Subsidiary or for
          all or substantially all of the property and assets of the
          Company, the Guarantor or any Significant Subsidiary or (C)
          effects any general assignment for the benefit of creditors.  

                    If an Event of Default (other than an Event of Default
          specified in clause (f) or (g) above that occurs with respect to
          the Company or the Guarantor) occurs and is continuing under the
          Indenture, the Trustee or the Holders of at least 25% in aggregate
          principal amount at maturity of the Notes, then outstanding, by
          written notice to the Company (and to the Trustee if such notice
          is given by the Holders), may, and the Trustee at the request of
          such Holders shall, declare the Accreted Value of, premium, if
          any, and accrued interest, if any, on the Notes to be immediately
          due and payable.

                    If an Event of Default, as defined in the Indenture,
          occurs and is continuing, the Trustee or the Holders of at least
          25% in principal amount at maturity of the Notes may declare all
          the Notes to be due and payable.  If a bankruptcy or insolvency
          default with respect to the Company or any Restricted Subsidiary
          occurs and is continuing, the Notes automatically become due and
          payable.  Holders may not enforce the Indenture or the Notes
          except as provided in the Indenture.  The Trustee may require
          indemnity satisfactory to it before it enforces the Indenture or
          the Notes.  Subject to certain limitations, Holders of at least a
          majority in principal amount at maturity of the Notes then
          outstanding may direct the Trustee in its exercise of any trust or
          power.

          16.  Guarantee.
               ---------

                    The Company's obligations under the Notes are fully and
          irrevocably guaranteed by the Guarantor.

          17.  Trustee Dealings with Company or Guarantor.
               ------------------------------------------

                    The Trustee under the Indenture, in its individual or
          any other capacity, may make loans to, accept deposits from and
          perform services for the Company, the Guarantor or their
          Affiliates and may otherwise deal with the Company, the Guarantor
          or their Affiliates as if it were not the Trustee.

          18.  No Recourse Against Others.
               --------------------------

                    No incorporator or any past, present or future partner,
          shareholder, other equity holder, officer, director, employee or
          controlling person as such, of the Company or the Guarantor or of
          any successor Person shall have any liability for any obligations
          of the Company or the Guarantor under the Notes or the Indenture
          or for any claim based on, in respect of or by reason of, such
          obligations or their creation.  Each Holder by accepting a Note
          waives and releases all such liability.  The waiver and release
          are part of the consideration for the issuance of the Notes.

          19.  Authentication.
               --------------

                    This Note shall not be valid until the Trustee or
          authenticating agent signs the certificate of authentication on
          the other side of this Note.

          20.  Abbreviations.
               -------------

                    Customary abbreviations may be used in the name of a
          Holder or an assignee, such as:  TEN COM (= tenants in common),
          TEN ENT (= tenants by the entireties), JT TEN (= joint tenants
          with right of survivorship and not as tenants in common), CUST
          (= Custodian) and U/G/M/A (= Uniform Gifts to Minors Act).

                    The Company will furnish to any Holder upon written
          request and without charge a copy of the Indenture.  Requests may
          be made to ICG Holdings, Inc., 9605 East Maroon Circle, P.O. Box
          6742, Englewood, Colorado, 80155-6742, Attention:  Chief Financial
          Officer.


                               [FORM OF TRANSFER NOTICE]


                    FOR VALUE RECEIVED the undersigned registered holder
          hereby sell(s), assign(s) and transfer(s) unto

          Insert Taxpayer Identification No.
          ----------------------------------

          ---------------------------------------------------------------
          ------------------------------------------
          Please print or typewrite name and address including zip code of
          assignee

          ---------------------------------------------------------------
          --------------------------------------------
          the within Note and all rights thereunder, hereby irrevocably
          constituting and appointing 
                                      -----------------------------------
                                       attorney to transfer said Note on the
          ----------------------------
          books of the Company with full power of substitution in the
          premises.


                        [THE FOLLOWING PROVISION TO BE INCLUDED
                   ON ALL SECURITIES OTHER THAN EXCHANGE SECURITIES,
                       UNLEGENDED OFFSHORE GLOBAL SECURITIES AND
                       UNLEGENDED OFFSHORE PHYSICAL SECURITIES]

               In connection with any transfer of this Note occurring prior
          to the date which is the earlier of (i) the date of an effective
          Registration or (ii) the end of the period referred to in Rule
          144(k) under the Securities Act, the undersigned confirms that
          without utilizing any general solicitation or general advertising
          that:

                                      [Check One]
                                       ---------

          [  ] (a)  this Note is being transferred in compliance with the
                    exemption from registration under the Securities Act of
                    1933, as amended, provided by Rule 144A thereunder.

                                          or
                                          --

          [  ] (b)  this Note is being transferred other than in accordance
                    with (a) above and documents are being furnished which
                    comply with the conditions of transfer set forth in this
                    Note and the Indenture.

          If none of the foregoing boxes is checked, the Trustee or other
          Registrar shall not be obligated to register this Note in the name
          of any Person other than the Holder hereof unless and until the
          conditions to any such transfer of registration set forth herein
          and in Section 2.08 of the Indenture shall have been satisfied.

          Date:
                                   NOTICE:  The signature to this assignment
                                   must correspond with the name as written
                                   upon the face of the within-mentioned
                                   instrument in every particular, without
                                   alteration or any change whatsoever.



          TO BE COMPLETED BY PURCHASER IF (a) ABOVE IS CHECKED.

               The undersigned represents and warrants that it is purchasing
          this Note for its own account or an account with respect to which
          it exercises sole investment discretion and that it and any such
          account is a "qualified institutional buyer" within the meaning of
          Rule 144A under the Securities Act of 1933, as amended, and is
          aware that the sale to it is being made in reliance on Rule 144A
          and acknowledges that it has received such information regarding
          the Company as the undersigned has requested pursuant to Rule 144A
          or has determined not to request such information and that it is
          aware that the transferor is relying upon the undersigned's
          foregoing representations in order to claim the exemption from
          registration provided by Rule 144A.

          Dated:
                                        NOTICE:  To be executed by an
                                        executive officer
           


          

                          OPTION OF HOLDER TO ELECT PURCHASE


                    If you wish to have this Note purchased by the Company
          pursuant to Section 4.11 or Section 4.12 of the Indenture, check
          the Box:  [ ]

                    If you wish to have a portion of this Note purchased by
          the Company pursuant to Section 4.11 or Section 4.12 of the
          Indenture, state the amount (in principal amount at maturity): 
          $___________________.

          Date:  
                 -----------------

          Your Signature:  
                                     (Sign exactly as your name appears on
          the other side of this Note)

          Signature Guarantee:  ______________________________