Exhibit 10.1

March 6, 2018
Corvex Management LP
667 Madison Avenue
New York, New York 10065
Attn:  Keith Meister
Ladies and Gentlemen:
Energen Corporation (the "Company"), on the one hand, and Corvex Management LP
("Corvex"), on the other hand, have mutually agreed to the terms contained in
this letter (this "Letter Agreement"). For purposes of this Letter Agreement, we
refer to each of the Company and Corvex as a "Party" and, collectively, as the
"Parties."
1. Board Composition and Related Matters.

                  (a)        Concurrently with the execution of this Letter
Agreement the Board of Directors of the Company (the "Board") shall expand the
size of the Board to eleven members and elect Jonathan Z. Cohen and Vincent J.
Intrieri (the "New Directors") as members of the Board to fill the two vacancies
created by such expansion, each with terms to expire at the Company's 2018
annual meeting of shareholders (the "2018 Annual Meeting").  The Company agrees
to include the New Directors in the slate of nominees recommended by the Board
in the proxy statement and proxy card relating to the 2018 Annual Meeting (the
"2018 Proxy Materials"), with Mr. Cohen nominated to serve in the class of
directors with terms expiring at the Company's 2021 annual meeting of
shareholders and Mr. Intrieri nominated to serve in the class of directors with
terms expiring at the Company's 2020 annual meeting of shareholders (the "2020
Annual Meeting").  The Company shall use its reasonable best efforts to cause
the election of the New Directors at the 2018 Annual Meeting (which, for the
avoidance of doubt, shall be no less than effort expended with respect to other
Company nominees) and shall recommend the Company's shareholders vote for the
election of the New Directors.  In connection with the foregoing, the Company
agrees that (i) Laurence M. Downes and Lori A. Lancaster (whose current terms
expire at the 2018 Annual Meeting) shall be nominated to serve in the class of
directors with terms expiring at the Company's 2019 annual meeting of
shareholders (the "2019 Annual Meeting") (which the Parties acknowledge shall
require Mr. Downes and Ms. Lancaster to be elected for a one-year term at the
2018 Annual Meeting) and (ii) William G. Hargett and Alan A. Kleier (whose
current terms also expire at the 2018 Annual Meeting) shall be nominated to
serve in the class of directors with terms expiring at the Company's 2021 annual
meeting of shareholders (the "2021 Annual Meeting").  The Company further agrees
(i) not to expand the size of the Board beyond eleven members at any time prior
to the 2019 Annual Meeting, (ii) except as set forth in the previous sentence,
not to change or seek to change the classes on which the directors (or their
replacements) serve, and (iii) to hold the 2018 Annual Meeting no later than May
31, 2018.  Based on the foregoing, and assuming the election of each of the
Company's nominees at the 2018 Annual Meeting (including Mr. Intrieri, Mr.
Cohen, Mr. Downes, Ms. Lancaster, Mr. Hargett and Mr. Kleier): (1) the class of
directors with terms expiring at the 2021 Annual Meeting shall be comprised of
Mr. Hargett, Mr. Kleier and Mr. Cohen; (2) the class of directors with terms
expiring at the 2020 Annual Meeting shall be comprised of Kenneth W. Dewey, M.
James Gorrie, James T. McManus, II and Mr. Intrieri; and (3) the class of
directors with terms expiring at the 2019 Annual Meeting shall be comprised of
Mr. Downes, Ms. Lancaster, Jay Grinney and Frances Powell Hawes.
                  (b)        The New Directors will use their respective
reasonable best efforts to obtain a waiver with respect to the "over-boarding"
policies of Institutional Shareholder Services and BlackRock, Inc., if
applicable, as soon as reasonably practicable, and if such waiver is not
obtained use their respective reasonable best efforts to comply with such
requirements prior to the one-year anniversary of this Letter Agreement.  In
furtherance of the foregoing, Corvex hereby agrees that it shall use its
reasonable best efforts to assist in procuring the compliance and obtaining of
any waiver contemplated by the preceding sentence, or in connection with any
replacement individual(s) who become members of the Board pursuant to paragraph
1(c), to the extent requested by the Company.
                  (c)        Should there be a vacancy or vacancies, for any
reason, as a result of the removal or resignation of one or both of the New
Directors or any other event resulting in one or both of the New Directors no
longer being a director, in each case, prior to the Company's mailing of
definitive proxy materials with respect to the 2019 Annual Meeting, then,
provided Mr. José Maria Alapont (i) meets all director independence and other
standards of the New York Stock Exchange and the Securities and Exchange
Commission (the "SEC"), (ii) provides to the Company all information that is
required to be included in a proxy statement filed pursuant to the proxy rules
of the SEC and New York Stock Exchange rules and regulations, (iii) complies
with and, where applicable, enters into all policies, codes of conduct,
confidentiality obligations and codes of ethics applicable to all of the
Company's directors, including consent to be named in the Company's proxy
materials and to serve as a director of the Company if elected, (iv) agrees to
use his or her reasonable best efforts to obtain a waiver with respect to the
"over-boarding" policies of Institutional Shareholder Services and BlackRock,
Inc., if applicable, as soon as reasonably practicable, and if such waiver is
not obtained use his or her reasonable best efforts to comply with such
requirements prior to the one-year anniversary of his election to the Board, and
(v) is not an employee, director, officer, controlling person or otherwise an
affiliate (as defined in Rule 12b-2 of the Securities Exchange Act of 1934, as
amended (the "Exchange Act")) of Corvex and/or its affiliates (the "Replacement
Requirements"), Corvex shall be entitled to designate him (or if he is no longer
able or willing to serve as a director or does not then satisfy the Replacement
Requirements, another individual (or, if there are two such vacancies, two other
individuals) satisfying the Replacement Requirements and reasonably acceptable
to the Board) in replacement of such individual(s) and the Company, the Board
and all applicable committees and subcommittees shall take all necessary actions
to (i) promptly appoint such individual(s) to fill such vacancy or vacancies
until the 2018 Annual Meeting or 2019 Annual Meeting, as applicable, and (ii)
nominate such individual(s) for election at the 2018 Annual Meeting or 2019
Annual Meeting, as applicable, to serve in the class of directors with the
applicable remaining term of the New Director(s) being replaced and such
replacement individual(s) shall be considered to be a "New Director" or "New
Directors", as the case may be, under this Agreement.  The Company shall use its
reasonable best efforts to cause the election of such New Director(s) at the
2018 Annual Meeting or 2019 Annual Meeting, as applicable (which, for the
avoidance of doubt, shall be no less than effort expended with respect to other
Company nominees) and shall recommend the Company's shareholders vote for the
election of such New Director(s). Corvex agrees that if a New Director resigns
from the Board, Corvex and its affiliates shall neither (1) nominate such
individual as a director nor (2) engage in, or encourage any third person to
engage in, any solicitation with respect to,  or vote in favor of or otherwise
directly or indirectly support, the election of such individual as a director,
in either case in connection with a contested solicitation of proxies at the
2019 Annual Meeting.  Notwithstanding anything to the contrary in this Letter
Agreement, Corvex's rights pursuant to this paragraph 1(c) shall terminate at
such time as Corvex no longer beneficially owns (as defined in Rule 13d-3 under
the Exchange Act) 5.0% or more of the outstanding common stock, $0.01 par value,
of the Company ("Common Stock").
 
                  (d)        The Company agrees that (i) the New Directors will
each be added to one or more committees of the Board (as determined by the full
Board), and (ii) if it forms any new committees or subcommittees of the Board,
the Board shall offer to the New Directors and, if accepted by the New
Directors, appoint such New Director or New Directors to such committee, as
applicable; provided that if any such new committee has four or fewer total
members, the Board shall only be required to offer one New Director the
opportunity to serve on such new committee (whom the New Directors shall be
entitled to select among themselves or, if they cannot agree, the Board shall
select), provided further, that the Board shall not form any strategic,
transaction or executive committee (or other committee with authority commonly
granted to such committees) or delegate authority commonly associated with such
committees to any existing committee unless both New Directors are offered to
the opportunity to sit on such committee (regardless of the number of members). 
The Board and any committees or subcommittees of the Board will not remove any
New Director from a committee of the Board, except as required by law, with
Corvex's prior written consent or if such New Director is no longer serving on
the Board.
 

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                  (e)        Corvex shall, and shall cause its affiliates to,
(i) in the case of all shares of Common Stock owned of record, as of the record
date for the 2018 Annual Meeting (which the Company hereby confirms is February
28, 2018), by Corvex or an affiliate, cause such shares, and (ii) in the case of
all shares of Common Stock beneficially owned but not owned of record, as of the
record date for the 2018 Annual Meeting, by Corvex or an affiliate, direct the
record holder to cause such shares (x) to be present for quorum purposes at the
2018 Annual Meeting and (y) to be voted in favor of (1) each director candidate
nominated by the Company, (2) the ratification of the appointment of
PricewaterhouseCoopers LLP as the independent registered public accounting firm
of the Company to audit the financial statements for calendar year 2018 and (3)
any "say-on-pay" proposal. Neither the Company nor Corvex shall knowingly take
any actions, including making any public statements, inconsistent with seeking
to effect the election of all of the nominees to the Board as set forth in the
2018 Proxy Materials.
 
                  (f)        Corvex shall promptly cause the appeal captioned
Corvex Management LP, Appellant, v. Energen Corporation, Appellee, docket No.
1170200, pending before the Supreme Court of Alabama to be voluntarily dismissed
with prejudice.
 
                  (g)        Concurrently with the execution of this Letter
Agreement, Corvex shall cause the Stockholder (as defined therein) to
irrevocably withdraw the Notice of Intent to Bring Business Before, and Nominate
Individuals for Election as Directors at, the 2018 Annual Meeting of
Stockholders of Energen Corporation submitted by the Stockholder to the Company
on January 31, 2018.
 
2. Press Release. The Parties agree that the Company will issue the press
release attached to this Letter Agreement as Exhibit A promptly (and in no event
later than March 7, 2018) following the execution and delivery of this Letter
Agreement by the Parties.
3. Counterparts. This Letter Agreement may be executed in two or more
counterparts, each of which will be considered one and the same agreement and
will become effective when counterparts have been signed by each of the Parties
and delivered to the other Party (including by means of electronic delivery or
facsimile).
4. Specific Performance. Each Party acknowledges and agrees that irreparable
injury to the other Party would occur in the event that any of the provisions of
this Letter Agreement were not performed in accordance with their specific terms
or were otherwise breached and that money damages are not an adequate remedy for
such a breach. Accordingly, the Parties hereby agree that in the event of any
breach or threatened breach by one of the Parties of any of its respective
covenants or obligations set forth in this Agreement, the other Party shall be
entitled to an injunction or injunctions to prevent or restrain breaches or
threatened breaches of this Agreement and to specifically enforce the terms and
provisions of this Agreement to prevent breaches or threatened breaches of, or
to enforce compliance with, the covenants and obligations of the other under
this Agreement. Each Party hereby agrees not to raise any objections to the
availability of the equitable remedy of specific performance to prevent or
restrain breaches or threatened breaches of this Agreement by such Party, and to
specifically enforce the terms and provisions of this Agreement to prevent
breaches or threatened breaches of, or to enforce compliance with, the covenants
and obligations of such Party under this Agreement; provided, however, that
nothing in this Letter Agreement shall prevent a Party from raising equitable
defenses in any such proceeding. Each Party agrees to waive any bonding
requirement under any applicable law in the case any other Party seeks to
enforce the terms of this Letter Agreement by way of equitable relief.
5. Applicable Law and Jurisdiction. This Letter Agreement will be governed by,
and enforced in accordance with, the laws of the State of Delaware without
reference to conflicts of laws principles (except that matters relating to the
internal affairs of the Company or the Board (including, without limitation, the
interpretation of the Company's certificate of incorporation and bylaws and the
Alabama Business and Nonprofit Entity Code) shall be governed by the internal
laws of the State of Alabama without reference to conflicts of laws principles).
Each of the Parties irrevocably agrees that any legal action or proceeding based
on or arising out of this Letter Agreement will be brought exclusively in the
Delaware Court of Chancery and any state appellate court therefrom within the
State of Delaware (or, if the Delaware Court of Chancery declines to accept
jurisdiction over a particular matter, any appropriate state or federal court
within the State of Delaware. Each of the Parties irrevocably waives the right
to trial by jury in any such action or proceeding. Each of the Parties hereby
irrevocably submits to the personal jurisdiction of the aforesaid courts for
purposes of any legal action or proceeding based on or arising out of this
Letter Agreement, and irrevocably waives any argument that such courts are an
inconvenient or improper forum for any such action or proceeding. Each Party
consents to service of process by a reputable overnight delivery service,
signature requested, to the address of such Party's principal place of business
or as otherwise provided by applicable law.
6. Notice. All notices, consents, requests, instructions, approvals and other
communications provided for herein and all legal process in regard hereto shall
be in writing and shall be deemed validly given, made or served, (a) if given by
telecopy, when such telecopy is transmitted, and the appropriate confirmation is
received or (b) if given by any other means, when actually received during
normal business hours at the principal executive office of Corvex or the
Company, as applicable, to the attention of such Party's Chief Executive
Officer.
7. Entire Agreement. This Letter Agreement, including exhibits and schedules
attached to this Letter Agreement, contains the entire understanding of the
Parties with respect to the subject matter hereof.
[Signature Page Follows]
 

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If the terms of this Letter Agreement are in accordance with your understanding,
please sign below and this Letter Agreement will constitute a binding agreement
among us.

ENERGEN CORPORATION
By: /s/James T. McManus, II                          
Name: James T. McManus, II
Title: Chairman, Chief Executive Officer and President

Acknowledged and agreed to as of the date
first written above:
CORVEX MANAGEMENT LP
 
By: /s/Keith Meister                                          
        Name: Keith Meister
        Title: Managing Partner

 
 
 

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EXHIBIT A
PRESS RELEASE
[attached as Exhibit 99.1]