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                                                                     EXHIBIT 4.1

                               THIRD AMENDMENT TO
                  FIRST AMENDED AND RESTATED CREDIT AGREEMENT

                 THIS THIRD AMENDMENT TO FIRST AMENDED AND RESTATED CREDIT
AGREEMENT (herein called this "Amendment") made as of the 15th day of November,
1995, by and among Holly Corporation ("Borrower"), Navajo Refining Company
("Navajo"), Holly Petroleum, Inc. ("Holly Petroleum"), Navajo Pipeline Co.
("Navajo Pipeline"), Navajo Holdings, Inc. ("Navajo Holdings"), Lea Refining
Company ("Lea"), Navajo Western Asphalt Company ("Navajo Western"), Montana
Refining Company, a Partnership ("Montana") and Navajo Crude Oil Marketing
Company ("Navajo Crude") (Navajo, Holly Petroleum, Navajo Pipeline, Navajo
Holdings, Lea, Navajo Western and Navajo Crude collectively referred to herein
as "Guarantors"), NationsBank of Texas, N.A., as Agent ("Agent"), and
NationsBank of Texas, N.A., Banque Paribas, The First National Bank of Boston,
and The Bank of Nova Scotia (collectively, "Lenders"),

                                  WITNESSETH:

                 WHEREAS, Borrower, Guarantors, Montana, Agent and Lenders have
entered into that certain First Amended and Restated Credit Agreement dated as
of July 23, 1993, as amended by that certain First Amendment to First Amended
and Restated Credit Agreement dated as of April 7, 1994, and by that certain
Second Amendment to First Amended and Restated Credit Agreement dated as of
June 13, 1995 (as so amended, the "Original Agreement"), for the purpose and
consideration therein expressed, whereby Lenders became obligated to make loans
to Borrower, and to issue letters of credit for the account of Borrower and
Montana, as therein provided; and

                 WHEREAS, Borrower, Guarantors, Montana, Agent and Lenders
desire to amend the Original Agreement for the purposes expressed herein;

                 NOW, THEREFORE, in consideration of the premises and the
mutual covenants and agreements contained herein and in the Original Agreement
and in consideration of the loans which may hereafter be made by Lenders to
Borrower and of the letters of credit which may hereafter be issued, extended
and renewed by Lenders for the account of Borrower and for the account of
Montana, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto do hereby
agree as follows:

                                       I.

                           DEFINITIONS AND REFERENCES

                 A.       Terms Defined in the Original Agreement. Unless the
context otherwise requires or unless otherwise expressly defined herein, the
terms defined in the Original Agreement shall have the same meanings whenever
used in this Amendment.





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                 B.       Other Defined Terms. Unless the context otherwise
requires, the following terms when used in this Amendment shall have the
meanings assigned to them in this Section 1.2.

                 "Amendment" shall mean this Third Amendment to First Amended
         and Restated Credit Agreement.

                 "Credit Agreement" shall mean the Original Agreement as
         amended hereby.

                                      II.

                        AMENDMENTS TO ORIGINAL AGREEMENT

                 A.   Defined Terms. The following definition of "Mandatory
Principal Payment" is hereby added to Section 1.1 of the Original Agreement
immediately following the definition of "Majority Banks":

                 "'Mandatory Principal Payment'. The aggregate mandatory
         principal payments that will be due on the Private Placement Date
         pursuant to the 1995 Private Placement Agreement and the Private
         Placement Agreement."

                 The definition of "Minimum Working Capital Requirements" in
Section 1.1 of the Original Agreement is hereby amended in its entirety to read
as follows:

                 "'Minimum Working Capital Requirements'. The Minimum Working
         Capital Requirements shall be satisfied at any time when Consolidated
         Current Assets minus Consolidated Current Liabilities equals or
         exceeds Fifteen Million Dollars ($15,000,000),except that the Minimum
         Working Capital Requirements shall be satisfied in each year
         commencing 1996, during the period from and including April 30 until
         but excluding the Private Placement Date, only if Consolidated Current
         Assets minus Consolidated Current Liabilities equals or exceeds the
         sum of $15,000,000 plus the Mandatory Principal Payment. For purposes
         of this paragraph, Consolidated Current Liabilities will be calculated
         without including any payments of principal on the notes issued under
         the Private Placement Agreement or the 1995 Private Placement
         Agreement which are required to be repaid within one year from the
         time of calculation."

                 The following definition of "1995 Private Placement Agreement"
is hereby added to Section 1.1 of the Original Agreement immediately following
the definition of "Navajo Western."

                 "'1995 Private Placement Agreement'. Those substantially
         similar Note Agreements, each dated as of November 15, 1995 providing
         for the issuance by Borrower of $39,000,000 in aggregate principal
         amount of its Series C Senior Notes due December 15, 2005 and of
         $21,000,000 in aggregate principal amount of its





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         Series D Notes due December 15, 2005, as the same may from time to
         time be amended."

                 The definition of "Private Placement Agreement" in Section 1.1
of the Original Agreement is hereby amended in its entirety to read as follows:

                 "'Private Placement Agreement'. Those substantially similar
         Note Agreements, each dated as of June 15, 1991, providing for the
         issuance by Borrower of $28,000,000 in aggregate principal amount of
         its Series A Senior Notes originally due June 15, 1998 and of
         $52,000,000 in aggregate principal amount of its Series B Senior Notes
         originally due June 15, 2001, as the same may from time to time be
         amended."

                 The definition of "Private Placement Date" in Section 1.1 of
the Original Agreement is hereby amended in its entirety to read as follows:

                 "'Private Placement Date'. So long as the Private Placement
         Agreement or the 1995 Private Placement Agreement is in effect, the
         date in each year commencing 1996 on which Borrower makes the required
         annual prepayments in respect of the notes issued under the Private
         Placement Agreement or the 1995 Private Placement Agreement."

                 The following definition of "Third Amendment" is hereby added
to Section 1.1 of the Original Agreement immediately following the definition
of "Subsidiary."

                 "'Third Amendment'. That certain Third Amendment to this
         Agreement dated as of November 15, 1995, by and among Borrower,
         Guarantors, Montana, Agent and Banks."

                 B.    Indebtedness. Section 7.1(j) of the Original agreement is
hereby amended in its entirety to read as follows:

                 "(j)  Indebtedness in an aggregate amount not to exceed
         $107,800,000 arising under the Private Placement Agreement, the 1995
         Private Placement Agreement and the guaranties thereof by the
         Guarantors and such other Subsidiaries as guarantee the Obligations
         from time to time, so long as the maturities, rates of interest,
         prepayment premiums and dates of payment do not differ materially from
         those set forth on Exhibit A to the Third Amendment;"

                 Section 2.3. Working Capital. Section 7.8 of the Original
Agreement is hereby amended in its entirety to read as follows:

                 "Section 7.8. Working Capital. The Related Persons shall not,
         at any time, permit Consolidated Current Assets minus Consolidated
         Current Liabilities to be less than Ten Million Dollars ($10,000,000)
         at any time, except that in each year commencing 1996, during the
         period from and including April 30 until but excluding the Private
         Placement Date, Consolidated Current Assets minus Consolidated Current
         Liabilities





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         shall not be less than the sum of $10,000,000 plus the Mandatory
         Principal Payment. For purposes of this Section 7.8, Consolidated
         Current Liabilities will be calculated without including any payments
         of principal on the notes issued under the Private Placement Agreement
         or the 1995 Private Placement Agreement which are required to be
         repaid within one year from the time of calculation."

                 Section 2.4. Borrower's Working Capital. Section 7.9 of the
Original Agreement is hereby amended in its entirety to read as follows:

                 "Section 7.9. Borrower's Working Capital. The Related Persons
         shall not, at any time, permit Consolidated Current Assets minus
         Consolidated Current Liabilities to be less than Five Million Six
         Hundred Thousand Dollars ($5,600,000), except that in each year
         commencing 1996, during the period from and including April 30 until
         but excluding the Private Placement Date, Consolidated Current Assets
         minus Consolidated Current Liabilities shall not be less than the sum
         of $5,600,000 plus the Mandatory Principal Payment. For purposes of
         this section only, the current assets and current liabilities of
         Montana and the Montana General Partners shall be excluded from the
         calculation of Consolidated Current Liabilities and Consolidated
         Current Assets. For purposes of this Section 7.9, Consolidated Current
         Liabilities will be calculated without including any payments of
         principal on the notes issued under the Private Placement Agreement or
         the 1995 Private Placement Agreement which are required to be repaid
         within one year from the time of calculation."

                 Section 2.5. Event of Default. Section 10(l) of the Original
Agreement is hereby amended in its entirety to read as follows:

                          "(l)    the aggregate principal amount of the notes
                 issued pursuant to either the Private Placement Agreement or
                 the 1995 Private Placement Agreement is increased, the rate of
                 interest or premium on such notes is increased from the rates
                 set forth on Exhibit A to the Third Amendment, or the
                 amortization schedule for such notes is modified without the
                 prior written consent of Majority Banks, or an event of
                 default shall occur and be continuing under the Private
                 Placement Agreement, the 1995 Private Placement Agreement or
                 any document or instrument executed and delivered in
                 connection therewith; or"

                                      III.

                          CONDITIONS OF EFFECTIVENESS

                 A.    Effective Date. This Amendment shall become effective
as of the date first above written when, and only when, (i) Agent shall have
received, at Agent's office, a counterpart of this Amendment executed and
delivered by Borrower, each Guarantor, Montana and each Lender, and (ii) Agent
shall have additionally received, in form and substance satisfactory to Agent,
certificates of the Secretary of Borrower and each Guarantor dated the date of
this Amendment certifying that (a) the persons named as authorized signatories
in prior Secretary's Certificates delivered to Agent (the "Prior Certificates")
are





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authorized to sign this Amendment, (b) the resolutions authorizing the
execution of the Loan Documents that were attached to the Prior Certificates
have not been amended, modified or revoked in any respect and are in full force
and effect on the date hereof and (c) that the charter documents of Borrower or
such Guarantor attached to the Prior Certificates have not been amended,
modified or revoked in any respect and are in full force and effect on the date
hereof.

                                      IV.

                         REPRESENTATIONS AND WARRANTIES

                 A.    Representations and Warranties of Related Persons. In
order to induce each Lender to enter into this Amendment, Borrower represents
and warrants as to itself and each other Related Person, and each other Related
Person represents and warrants as to itself, to each Lender that:

                       1.    The representations and warranties contained in
         Section 5.1 of the Original Agreement are true and correct at and as
         of the time of the effectiveness hereof.

                       2.    Each of Borrower, each Guarantor and Montana is 
         duly authorized to execute and deliver this Amendment, and Borrower is
         and will continue to be duly authorized to borrow monies and to perform
         its obligations under the Credit Agreement. Each of Borrower, each
         Guarantor and Montana has duly taken all corporate or partnership
         action necessary to authorize the execution and delivery of this
         Amendment and to authorize the performance of its obligations
         hereunder.
        
                       3.    The execution and delivery by each of Borrower,  
         each Guarantor and Montana of this Amendment, the performance by such
         Person of its obligations hereunder and the consummation of the
         transactions contemplated hereby do not and will not conflict with any
         provision of law, statute, rule or regulation or of any of its
         organizational documents, or of any material agreement, judgment,
         license, order or permit applicable to or binding upon it, or result in
         the creation of any lien, charge or encumbrance upon any assets or
         properties or any of its assets. Except for those which have been
         obtained, no consent, approval, authorization or order of any court or
         governmental authority or third party is required in connection with
         the execution and delivery by any of Borrower, any Guarantor or Montana
         of this Amendment or to consummate the transactions contemplated
         hereby.
        
                       4.    When duly executed and delivered, this Amendment 
         will be a legal and binding obligation of Borrower, Guarantors and
         Montana enforceable in accordance with its terms, except as limited by
         bankruptcy, insolvency or similar laws of general application relating
         to the enforcement of creditors' rights and by equitable principles of
         general application.





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                                       V.

                                 MISCELLANEOUS

                 A.       Ratification of Agreements. The Original Agreement as
hereby amended is hereby ratified and confirmed in all respects. Any reference
to the Credit Agreement in any Loan Document shall be deemed to be a reference
to the Original Agreement as hereby amended. The execution, delivery and
effectiveness of this Amendment shall not, except as expressly provided herein,
operate as a waiver of any right, power or remedy of Lenders under the Credit
Agreement, the Notes or any other Loan Document nor constitute a waiver of any
provision of the Credit Agreement, the Notes or any other Loan Document. Each
Guarantor hereby consents to the provisions of this Amendment and the
transactions contemplated herein, and hereby ratifies and confirms the
Guaranty, and agrees that its obligations and covenants thereunder are
unimpaired hereby and shall remain in full force and effect.

                 B.       Survival of Agreements. All representations,
warranties, covenants and agreements of each of Borrower, Guarantors and
Montana herein shall survive the execution and delivery of this Amendment and
the performance hereof, including without limitation the making or granting of
the Loans, and shall further survive until all of the Obligations are paid in
full. All statements and agreements contained in any certificate or instrument
delivered by Borrower, any Guarantor or Montana hereunder or under the Credit
Agreement to any Lender shall be deemed to constitute representations and
warranties by, and/or agreements and covenants of, such Person under this
Amendment and under the Credit Agreement.

                 C.       Loan Documents. This Amendment is a Loan Document,
and all provisions in the Credit Agreement pertaining to Loan Documents apply
hereto.

                 D.       Governing Law. This Amendment shall be governed by
and construed in accordance with the laws of the State of Texas and any
applicable laws of the United States of America in all respects, including
construction, validity and performance.

                 E.       Counterparts. This Amendment may be separately
executed in counterparts and by the different parties hereto in separate
counterparts, each of which when so executed shall be deemed to constitute one
and the same Amendment.

                 THIS WRITTEN AGREEMENT AND THE OTHER LOAN DOCUMENTS REPRESENT
THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE
OF PRIOR, CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES.

                 THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES.





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                 IN WITNESS WHEREOF, this Amendment is executed as of the date
first above written.
                                                 
                                        HOLLY CORPORATION,
                                        a Delaware corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President, Treasurer 
                                            and Controller


                                        NAVAJO REFINING COMPANY,
                                        a Delaware corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 


                                        NAVAJO PIPELINE CO.,
                                        a Delaware corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 



                                        NAVAJO HOLDINGS, INC.,
                                        a New Mexico corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 





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                                        HOLLY PETROLEUM, INC.,
                                        a Delaware corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 



                                        LEA REFINING COMPANY,
                                        a Delaware corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 


                                        NAVAJO WESTERN ASPHALT
                                        COMPANY, a New Mexico corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 


                                        MONTANA REFINING COMPANY,
                                        A PARTNERSHIP,
                                        a Montana general partnership

                                        By: Navajo Northern, Inc., its General
                                            Partner and a Nevada corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 






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                                        NAVAJO CRUDE OIL MARKETING
                                        COMPANY, a Texas corporation

                                        By: /s/ HENRY A. TEICHHOLZ
                                            ------------------------------------
                                            Henry A. Teichholz
                                            Vice President and Treasurer 



                                        NATIONSBANK OF TEXAS, N.A.,
                                        as Agent

                                        By: /s/ E. MURPHY MARKHAM, IV
                                            ------------------------------------
                                            E. Murphy Markham, IV
                                            Senior Vice President


                                        BANQUE PARIBAS

                                        By: /s/ MARIAN LIVINGSTON
                                            ------------------------------------
                                            Marian Livingston
                                            Vice President


                                        By: /s/ BRIAN MALONE
                                            ------------------------------------
                                            Brian Malone
                                            Vice President


                                        THE FIRST NATIONAL BANK OF
                                        BOSTON

                                        By: /s/ H. LOUIS BAILEY
                                            ------------------------------------
                                            H. Louis Bailey
                                            Director





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                                        THE BANK OF NOVA SCOTIA

                                        By: /s/ F.C.H. ASHBY
                                            ------------------------------------
                                            F.C.H. Ashby
                                            Senior Manager Loan Operations


                                        NATIONSBANK OF TEXAS, N.A.

                                        By: /s/ E. MURPHY MARKHAM, IV
                                            ------------------------------------
                                            E. Murphy Markham, IV
                                            Senior Vice President





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