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                                                                    EXHIBIT 5.1



                                CARLTON FIELDS
                               ATTORNEYS AT LAW

       ONE HARBOUR PLACE                                MAILING ADDRESS:
777 S. HARBOUR ISLAND BOULEVARD             P.O. BOX 3239, TAMPA, FL 33601-3239
  TAMPA, FLORIDA 33602-5799                TEL (813) 223-7000 FAX (813) 229-4133

                                October 12, 1999

Northeast Bancorp
232 Center Street
Auburn, Maine 04210
Attention: Board of Directors

NBN Capital Trust
c/o Northeast Bancorp
232 Center Street
Auburn, Maine 04210
Attention: Administrators


         RE: NBN CAPITAL TRUST
             $12,075,000 LIQUIDATION AMOUNT
             OF PREFERRED SECURITIES


Ladies and Gentlemen:

         We have acted as counsel to Northeast Bancorp, a Maine corporation
(the "Company"), in connection with the preparation and filing by the Company
and NBN Capital Trust, a Delaware statutory business trust (the "Trust"), of a
registration statement on Form S-2 (the "Registration Statement"), with the
United States Securities and Exchange Commission under the Securities Act of
1933, as amended (the "Act"), with respect to the offer and sale of certain of
the Trust's Preferred Securities (liquidation amount $10 per Preferred
Security) (the "Preferred Securities") and certain of the Company's Junior
Subordinated Debentures (the "Debentures") and the related Guarantee Agreement
(the "Guarantee") by and between the Company and the Bankers Trust Company, as
trustee (the "Trustee"). In connection therewith, you have requested our
opinion as to certain matters referred to below.

         In our capacity as such counsel, we have familiarized ourselves with
the actions taken by the Company in connection with the registration of the
Debentures and the Guarantee. We have examined originals or copies, certified
or otherwise identified to our satisfaction, of such records,

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Northeast Bancorp
NBN Capital Trust
October 12, 1999
Page 2

agreements, certificates or comparable documents of public officials and
others, and such other documents as we have deemed relevant and necessary as a
basis for the opinions hereinafter expressed, including, without limitation,
(i) the Articles of Incorporation and Bylaws of the Company, (ii) the form of
Preferred Securities, (iii) the form of Debenture and Guarantee, (iv) the form
of the Junior Subordinated Debenture Indenture (the "Indenture") between the
Company and the Trustee, as trustee, (v) the opinion of Lipman & Katz, P.A.,
Augusta, Maine, relating to certain Maine corporate law matters, and (v) the
Registration Statement.

         In our examination, we have assumed legal capacity of all natural
persons, the genuineness of all signatures on original documents, the
authenticity of all documents submitted to us as originals, the conformity to
original documents of all copies submitted to us as conformed or photostatic
copies, the authenticity of the originals of such latter documents, and the
accuracy and completeness of all corporate records made available to us by the
Company and the Trust. We also have assumed the authority of such persons
signing on behalf of parties thereto other than the Company or the Trust, and
the due authorization, execution, and delivery of all documents by the parties
thereto other than the Company or the Trust.

         Based upon and subject to the foregoing, we are of the opinion that
the Guarantee, when executed and delivered as contemplated by the Registration
Statement, and the Debentures, when issued and paid for as contemplated by the
Registration Statement, subject to (i) the effectiveness of the Registration
Statement by order of the Securities and Exchange Commission, (ii) compliance
with the terms of the Indenture, and (iii) compliance with applicable state
securities laws, the Debentures and the Guarantee will be validly issued and
binding obligations of the Company, enforceable in accordance with their terms,
except as may be limited by bankruptcy, insolvency, moratorium, reorganization,
or similar laws relating to or affecting the enforcement of creditors' rights
generally or the rights of creditors of bank holding companies, the accounts of
whose subsidiaries are insured by the Federal Deposit Insurance Corporation, or
by general equity principles, regardless of whether such obligation is
considered in a proceeding in equity or at law.

         The opinion set forth above is subject to the exception that we
express no opinion as to the present or future value of any Debentures or the
Guarantee issued or delivered as described above or in the Registration
Statement.

         We are attorneys admitted to practice in the State of Florida and,
accordingly, our opinion is limited to the laws of the State of Florida, the
General Corporation Law of the State of Delaware, and with the federal laws of
the United States of America. With respect to the Debentures and the Guarantee,
which are stated to be governed by the laws of the State of New York, we have
assumed with your consent that such laws are the same as the laws of the State
of Florida with respect to the legal, valid, and binding nature of the
Debentures and the Guarantee.

         This opinion is rendered to you and for your benefit solely in
connection with the registration of the Debentures and the execution and
delivery of the Guarantee. This opinion may not be relied

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Northeast Bancorp
NBN Capital Trust
October 12, 1999
Page 3

upon by you for any other purpose and may not be relied upon by, nor may copies
thereof be provided to, any other person, firm, corporation or entity for any
purposes whatsoever without our prior written consent. We hereby consent to be
named in the Registration Statement and in the Prospectus as the attorneys who
passed upon the legality of the Debentures and the Guarantee, and to the filing
of a copy of this opinion as an exhibit to the Registration Statement. Unless
the prior written consent of our firm is obtained, this opinion is not to be
quoted or otherwise referred to in any written report, proxy statement or other
registration statement, nor is it to be filed with or furnished to any other
governmental agency or other person, except as otherwise required by law.



                                             Very truly yours,

                                             CARLTON, FIELDS, WARD, EMMANUEL,
                                               SMITH & CUTLER, P.A.



                                             By: /s/ Richard A. Denmon
                                                -------------------------------
                                                     Richard A. Denmon
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                       (LIPMAN & KATZ, P. A. LETTERHEAD)



                                October 12, 1999



Northeast Bancorp
232 Center Street
Auburn, Maine 04210
Attention: Board of Directors

NBN Capital Trust
c/o Northeast Bancorp
232 Center Street
Auburn, Maine 04210
Attention: Administrators

Carlton Fields Ward Emmanuel Smith & Cutler., P.A.
One Harbour Place
777 South Harbour Island Boulevard
Tampa, Florida 33602


              RE:  NORTHEAST BANCORP
                   NBN CAPITAL TRUST
                   $12,075,000 LIQUIDATION AMOUNT OF TRUST PREFERRED SECURITIES
                   REGISTRATION STATEMENT ON FORM S-2


Gentlemen:

         We have acted as limited special corporate counsel to Northeast
Bancorp, a Maine corporation (the "Company"), in connection with the
Registration Statement on Form S-2 (the "Registration Statement") of the
Company and NBN Capital Trust, a Delaware business trust (the "Trust") to be
filed with the United States Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended, with respect to the
offer and sale of certain of the Trust's Preferred Securities (liquidation
amount $10 per Preferred Security) and certain of the Company's Junior
Subordinated Debentures (the "Debentures") and the related Guarantee Agreement
(the "Guarantee") by and between the Company and the Bankers Trust Company, as
trustee (the "Trustee"). In connection therewith, you have requested our
opinion as to certain matters referred to below. The Debentures and the
Guarantee are referred to together herein as the "Indenture Obligations".



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         In connection with this opinion, we have examined the copies of (a)
the Junior Subordinated Indenture pursuant to which the Debenture will be
issued, (b) the Guarantee, and (c) the Registration Statement, in the
substantially the form in which it will be filed with the Commission on October
12, 1999 and the Prospectus which is a part thereof. In addition, we have
examined and are familiar with originals or copies, certified or otherwise
identified to our satisfaction, of all such corporate records, instruments, and
documents of the Company, certificates of public, and other certificates and
documents as we have deemed appropriate for rendering our opinions set forth
below.

         In our examination, we have assumed the genuineness of all signatures,
the legal capacity of all natural persons, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents to us as certified or photostatic copies and the authenticity of the
original of such documents. As to any facts material to the opinions expressed
below, with your permission we have relied solely upon, without independent
verification or investigation of the accuracy or completeness hereof,
statements and representations of the officers and other representatives of the
Company.

         Based solely on the foregoing, and in reliance thereon, and subject to
the limitations, qualifications and exceptions set forth herein, we are of the
opinion that:

         1. The Company is a corporation duly organized, validly existing and
in good standing under the laws of the State of Maine and has the requisite
corporate power and authority to own its properties and to conduct its business
as described in the Registration Statement.

         2. The Company has the full power and authority (corporate and other)
to execute, deliver, and perform its obligations under each of the Indenture
Obligations. The execution and delivery by the Company of each of the Indenture
Obligations and the performance by the Company of its obligations thereunder
have been duly authorized by all requisite corporate action on the part of the
Company.

         3. Neither the execution and delivery of the Indenture Obligations,
nor the performance by the Company of its obligations thereunder or
contemplated therein, will conflict with, or result in a violation of the
Articles of Incorporation or Bylaws of the Company or the Maine General
Corporation Law.

         The opinions set forth above are subject to the following limitations,
qualifications, and exceptions:

         A. We express no opinion as to the law of any jurisdiction, except the
laws of the State of Maine and, where applicable, the laws of the United States
of America to the extent specifically provided above.

         B. Without limiting the generality of the foregoing, we express no
opinion as to the applicability of any securities laws or regulations except to
the extent specifically provided above in this opinion, or bankruptcy or
solvency laws or regulations, or environmental law or regulations of the United
States of America or any state or other jurisdiction.




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         This opinion is limited to the laws in effect as of the date hereof
and is intended solely for your benefit, and can be relied upon solely by you.
This opinion is not to be furnished, quoted, or referenced to anyone else,
including any governmental agency, without the prior written consent of this
firm. We hereby consent to be named in the Registration Statement and in the
Prospectus as the attorneys who passed upon the legality of the Debentures and
the Guarantee, and to the filing of a copy of this opinion as an exhibit to the
Registration Statement. Unless the prior written consent of our firm is
obtained, this opinion is not to be quoted or otherwise referred to in any
written report, proxy statement or other registration statement, nor is it to
be filed with or furnished to any other governmental agency or other person,
except as otherwise required by law.


                                          Very truly yours,

                                          LIPMAN & KATZ, P.A.



                                          By: /s/ Sumner H. Lipman
                                             ----------------------------------
                                                  Sumner H. Lipman