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                                                                    Exhibit 10.1

                                STORAGE USA, INC.
                           175 TOYOTA PLAZA, SUITE 700
                            MEMPHIS, TENNESSEE 38103


October 31, 2001

Security Capital Group Incorporated
125 Lincoln Avenue
Santa Fe, New Mexico 87501

Re:  Modification of Standstill through November 21, 2001

Ladies and Gentlemen:

        Reference is made to that certain Letter Agreement (the "September
Letter") dated as of September 7, 2001 by and among Storage USA, Inc., a
Tennessee corporation (the "Company"), SUSA Partnership, L.P., a Tennessee
limited partnership (the "Operating Partnership"), Storage USA Trust, a Maryland
real estate investment trust and a wholly owned subsidiary of the Company (the
"Trust") and Security Capital Group Incorporated (both as to itself and as
successor to all the rights of USREALTY and Buyer under the Strategic Alliance
Agreement, "Security Capital") and to that certain Letter Agreement (the
"October Letter" and together with the September Letter, the "Previous Letters")
dated as of October 7, 2001 by among the parties hereto. Terms used herein but
not defined shall have the meanings given to them in the September Letter.

        In light of the Special Committee's determination that it is advisable
for the Company to receive a proposal from Security Capital with respect to a
Covered Transaction, the Company hereby agrees to waive the provisions of
Section 5.2(a)(iv) of the Strategic Alliance Agreement to the extent, but only
to the extent, necessary to permit Security Capital, if it so desires, to make a
proposal to effect a Covered Transaction with the Company and to engage in
further discussions with the Special Committee and its agents and
representatives concerning the terms and conditions of any such proposal. It is
explicitly understood and agreed that unless extended in a writing signed by
both the Company and Security Capital the limited waiver contained in this
paragraph will terminate on November 21, 2001.

        It is further understood and agreed, and the limited waiver granted in
the immediately preceding paragraph is given by the Company on the express
condition that nothing contained herein, in the Previous Letters or in any
previous or future discussions between the parties or their representatives
shall be deemed to in any other way waive or modify any of the provisions of the
Strategic Alliance Agreement, but that those provisions otherwise shall remain
in effect, modified only to the extent provided in the preceding paragraph. The
parties hereby confirm that this letter agreement contains the only
modifications and waivers to the Strategic Alliance Agreement that remain in
effect on the date hereof.


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Security Capital Group Incorporated
October 31, 2001
Page 2


        For the avoidance of doubt, the parties hereto agree that (i) any
actions taken by the Company or the Special Committee or any of their respective
agents or representatives prior to the execution hereof in accordance with the
actions of the Board of Directors of the Company authorizing and forming the
Special Committee of the Board of Directors, any actions taken by the parties
hereto authorized by such authorization, the related resolutions or the Previous
Letters and any contacts, discussions or negotiations between the parties and/or
their affiliates or representatives, in each case prior to the execution hereof,
and (ii) the negotiation and entering into of this letter agreement, shall not,
in any event, constitute an "Early Termination Event" under Section 5.1 of the
Strategic Alliance Agreement or constitute a violation or attempted violation by
any of the parties of any provision of the Strategic Alliance Agreement
(including, without limitation, Sections 2.2, 5.1 and 5.2 thereof), or of any
provision of the Company's Charter or Amended and Restated Bylaws, and each of
the parties hereto hereby irrevocably waives any claim against any of the other
parties, its directors, officers, employees, and representatives, or their
affiliates because of any such contacts, actions, discussions or negotiations to
the extent permitted hereby or to the extent that such actions were permitted at
such time by the Previous Letters.

        We understand that in accordance with applicable law and regulations,
this letter will be publicly disclosed and filed as part of an amendment to your
Schedule 13D with respect to your ownership of Company stock. Likewise, you
understand that we intend to file a copy of this letter with a Form 8-K
announcing the signing of this agreement.

                               Very truly yours,

                               STORAGE USA, INC.



                               By:   /s/ Dean Jernigan
                                     ----------------------------------------
                                     Name:  Dean Jernigan
                                     Title: Chairman, Chief Executive Officer
                                            and President


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Security Capital Group Incorporated
October 31, 2001
Page 3



                               SUSA PARTNERSHIP, L.P.


                               By:   Storage USA, Inc., General Partner

                               By:   /s/ Dean Jernigan
                                     ----------------------------------------
                                     Name:  Dean Jernigan
                                     Title: Chairman, Chief Executive Officer
                                            and President

                               STORAGE USA TRUST

                               By:   /s/ Dean Jernigan
                                     ----------------------------------------
                                     Name:  Dean Jernigan
                                     Title: Chairman, Chief Executive Officer
                                            and President

Agreed to and accepted by:

SECURITY CAPITAL GROUP INCORPORATED


By:      /s/ C. Ronald Blankenship
         ------------------------------------------------
         Name:  C. Ronald Blankenship
         Title: Vice Chairman and Chief Operating Officer