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Exhibit 10.18  Shareholder's Agreement


                             SHAREHOLDER'S AGREEMENT


This Shareholder's Agreement ("Agreement"), dated as of December __, 1999 is
entered into by and between Western Sierra Bancorp, a California corporation
("Bancorp"), and ______________________ ("Shareholder").


                                    RECITALS

A.   Bancorp, Western Sierra National Bank and Sentinel Community Bank, a
     federal savings and loan association ("SCB") entered into that certain
     Agreement and Plan of Reorganization and Merger dated as of December __,
     1999 (the "Reorganization Agreement").

B.   Shareholder is a member of the Board of Directors of SCB and owns shares of
     the common stock, ___ par value, of SCB ("SCB Stock").

C.   Shareholder is willing to agree to vote or cause to be voted all shares of
     SCB Stock with respect to which Shareholder has voting power on the date
     hereof or hereafter acquired to approve the Reorganization Agreement and
     the transactions contemplated thereby and all requisite matters related
     thereto.

D.   Shareholder is willing to agree to not compete with, use trade secrets or
     solicit customers or employees of Bancorp or any of Bancorp's Subsidiaries,
     or SCB as set forth in this Agreement.

E.   Unless otherwise provided in this Agreement, capitalized terms shall have
     the meanings given to them in the Reorganization Agreement.

NOW THEREFORE, in consideration of the premises and of the respective
representations, warranties and covenants, agreements and conditions contained
herein and in the Reorganization Agreement, and intending to be legally bound
hereby, Bancorp and Shareholder agree as follows:


                                    ARTICLE I

                             SHAREHOLDER'S AGREEMENT

     1.1  AGREEMENT TO VOTE. Shareholder shall vote or cause to be voted at any
meeting of shareholders of SCB to approve the Reorganization Agreement and the
transactions contemplated thereby (the "Shareholders' Meeting"), all of the
shares of SCB Stock as to which Shareholder has sole or shared voting power (the
"Shares"), as of the record date established to determine shareholders who have
the right to vote at any such Shareholders' Meeting or to give consent to action
in writing (the "Record Date"), to approve the Reorganization Agreement, the
Agreement to Merge and the transactions contemplated thereby, including the
principal terms of the Reorganization and Merger.

     1.2  LEGEND. Shareholder agrees to stamp, print or type on the face of his
or her certificates of SCB Stock evidencing the Shares the following legend:

          "THE VOTING, SALE, ASSIGNMENT, TRANSFER, PLEDGE, HYPOTHECATION OR
          OTHER ENCUMBRANCE OR DISPOSITION OF THE


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          SHARES REPRESENTED BY THIS CERTIFICATE IS SUBJECT TO A SHAREHOLDER'S
          AGREEMENT DATED AS OF DECEMBER __, 1999 BY AND BETWEEN WESTERN SIERRA
          BANCORP, AND ____________________________, COPIES OF WHICH ARE ON FILE
          AT THE OFFICES OF SENTINEL COMMUNITY BANK."

     1.3  RESTRICTIONS ON DISPOSITIONS. Shareholder agrees that, from and after
the date of this Agreement and during the term of this Agreement, he or she will
not take any action that will alter or affect in any way the right to vote the
Shares, except (i) with the prior written consent of Bancorp or (ii) to change
such right from that of a shared right of Shareholder to vote the Shares to a
sole right of Shareholder to vote the Shares.

     1.4  SHAREHOLDER APPROVAL. Shareholder shall (i) recommend shareholder
approval of the Reorganization Agreement, the Agreement to Merge and the
transactions contemplated thereby by the SCB shareholders at the Shareholders'
Meeting and (ii) advise the SCB shareholders to reject any subsequent proposal
or offer received by SCB relating to any purchase, sale, acquisition, merger or
other form of business combination involving SCB or any of its assets, equity
securities or debt securities and to proceed with the transactions contemplated
by the Reorganization Agreement; provided, however, that Shareholder shall not
be obligated to take any action specified above if the Board of Directors of SCB
is advised in writing by outside legal counsel, Bartel Eng Linn & Schroder,
that, in the exercise of his or her fiduciary duties, a director of SCB should
not take such action.

     1.5  NONCOMPETITION. For a period of two years after the Effective Time of
the Reorganization, Shareholder agrees not to, directly or indirectly, without
the prior written consent of Bancorp, own more than 1% of, organize, manage,
operate, finance or participate in the ownership, management, operation or
financing of, or be connected as an officer, director, employee, principal,
agent or consultant to any financial institution whose deposits are insured by
the Federal Deposit Insurance Corporation that has its head offices or a branch
office within 50 miles of the head office of SCB. In the event that during the
two year period Bancorp is acquired by another financial institution and is not
the surviving entity of the acquisition, then this Section 1.5 shall terminate
upon the date of Bancorp's acquisition.


                                   ARTICLE II

                  REPRESENTATIONS AND WARRANTIES OF SHAREHOLDER

Shareholder represents and warrants to Bancorp that the statements set forth
below are true and correct as of the date of this Agreement, except those that
are specifically as of a different date:


     2.1  OWNERSHIP AND RELATED MATTERS.

         (a) SCHEDULE 2.1(a) hereto correctly sets forth the number of Shares
and the nature of Shareholder's voting power with respect thereto as of the date
hereof. Within five business days after the Record Date, Shareholder shall amend
said Schedule 2.1(a) to correctly reflect the number of Shares and the nature of
Shareholder's voting power with respect thereto as of the Record Date.

         (b) There are no proxies, voting trusts or other agreements or
understandings to or by which Shareholder or his or her spouse is a party or
bound or that expressly requires that any of the Shares be voted in any specific
manner other than as provided in this Agreement.


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     2.2  AUTHORIZATION; BINDING AGREEMENT. Shareholder has the legal right,
power, capacity and authority to execute, deliver and perform this Agreement,
and this Agreement is the valid and binding obligation of Shareholder
enforceable in accordance with its terms, except as the enforcement thereof may
be limited by general principles of equity.

     2.3  NONCONTRAVENTION. The execution, delivery and performance of this
Agreement by Shareholder will not (a) conflict with or result in the breach of,
or default or actual or potential loss of any benefit under, any provision of
any agreement, instrument or obligation to which Shareholder or his or her
spouse is a party or by which any of Shareholder's properties or his or her
spouse's properties are bound, or give any other party to any such agreement,
instrument or obligation a right to terminate or modify any term thereof; (b)
require any third party consents; (c) result in the creation or imposition of
any encumbrance on any of the Shares or any other assets of Shareholder or his
or her spouse; or (d) violate any applicable laws or rules to which Shareholder
or his or her spouse is subject.


                                   ARTICLE III

                                     GENERAL

     3.1  AMENDMENTS. To the fullest extent permitted by law, this Agreement and
any schedule or exhibit attached hereto may be amended by agreement in writing
of the parties hereto at any time.

     3.2  INTEGRATION. This Agreement constitutes the entire agreement between
the parties pertaining to the subject matter hereof and (except for the
Reorganization Agreement if executed by Shareholder) supersedes all prior
agreements and understandings of the parties in connection therewith.

     3.3  SPECIFIC PERFORMANCE. Shareholder and Bancorp each expressly
acknowledge that, in view of the uniqueness of the obligations of Shareholder
contemplated hereby, Bancorp would not have an adequate remedy at law for money
damages in the event that this Agreement has not been performed by Shareholder
in accordance with its terms, and therefore Shareholder and Bancorp agree that
Bancorp shall be entitled to specific enforcement of the terms hereof in
addition to any other remedy to which it may be entitled at law or in equity.

     3.4  TERMINATION. This Agreement shall terminate automatically without
further action at the earlier of two years following the Effective Time of the
Reorganization or the termination of the Reorganization Agreement in accordance
with its terms. Upon termination of this Agreement as provided herein, the
respective obligations of the parties hereto shall immediately become void and
have no further force and effect.

     3.5  NO ASSIGNMENT. Neither this Agreement nor any rights, duties or
obligations hereunder shall be assignable by Bancorp or Shareholder, in whole or
in part. Any attempted assignment in violation of this prohibition shall be null
and void. Subject to the foregoing, all of the terms and provisions hereof shall
be binding upon, and inure to the benefit of, the successors of the parties
hereto.

     3.6  HEADINGS. The descriptive headings of the several Articles and
Sections of this Agreement are inserted for convenience only and do not
constitute a part of this Agreement.

     3.7  COUNTERPARTS. This Agreement may be executed in one or more
counterparts, all of which shall be considered one and the same agreement and
shall become effective when one or more counterparts have been signed by each
party hereto and delivered to each party hereto.


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     3.8  GENDER, NUMBER, AND TENSE. Throughout this Agreement, unless the
context otherwise requires,

          (i)    the masculine, feminine and neuter genders each includes the
                 other;

          (ii)   the singular includes the plural, and the plural includes the
                 singular; and

          (iii)  the past tense includes the present, and the present tense
                 includes the past.

     3.9  NOTICES. Any notice or communication required or permitted hereunder,
shall be deemed to have been given if in writing and (a) delivered in person,
(b) delivered by confirmed facsimile transmission, or (c) mailed by certified or
registered mail, postage prepaid with return receipt requested, addressed as
follows:


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     IF TO BANCORP:

         WESTERN SIERRA BANCORP
         4011 PLAZA GOLDORADO CIRCLE
         CAMERON PARK, CALIFORNIA 95682
         ATTENTION: GARY D. GALL
         FAX:  (530) 677-5075

     WITH A COPY TO:

         GARY STEVEN FINDLEY & ASSOCIATES
         1470 NORTH HUNDLEY STREET
         ANAHEIM, CALIFORNIA 92806
         ATTENTION:  GARY STEVEN FINDLEY
         FAX:  (714) 630-7910

     IF TO SHAREHOLDER:

         ----------------------------

         ----------------------------

         ----------------------------

or at such other address and to the attention of such other person as a party
may notice to the other in accordance with this Section 3.9. Any such notice or
communication shall be deemed received on the date delivered personally or
delivered by confirmed facsimile transmission or on the third Business Day after
it was sent by certified or registered mail, postage prepaid with return receipt
requested.

     3.10  GOVERNING LAW. This Agreement shall be construed in accordance with,
and governed by, the laws of the State of California, except to the extent
preempted by the laws of the United States.

     3.11  NOT IN DIRECTOR CAPACITY. Except to the extent set forth in Section
1.4, no person executing this Agreement who is, during the term hereof, a
director of SCB, makes any agreement or understanding herein in his or her
capacity as such director. The parties sign solely in their capacities as owners
of or holders of the power to vote shares of SCB Stock.

     3.12  ATTORNEYS' FEES. If any legal action or any arbitration upon mutual
agreement is brought for the enforcement of this Agreement or because of an
alleged dispute, breach or default in connection with this Agreement, the
prevailing party shall be entitled to recover reasonable attorneys' fees and
other costs and expenses incurred in that action or proceeding, in addition to
any other relief to which it may be entitled.

     3.13  REGULATORY COMPLIANCE. Each of the provisions of this Agreement is
subject to compliance with all applicable regulatory requirements and
conditions.

IN WITNESS WHEREOF, the parties to this Agreement have caused and duly executed
this Agreement as of the day and year first above written.

                                     WESTERN SIERRA BANCORP


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                                     By:
                                        ---------------------------------
                                     Title: President

                                     SHAREHOLDER




                                     ------------------------------------


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                                 SPOUSAL CONSENT

I am the spouse of _______________________, Shareholder in the above Agreement.
I understand that I may consult independent legal counsel as to the effect of
this Agreement and the consequences of my execution of this Agreement and, to
the extent I felt it necessary, I have discussed it with legal counsel. I hereby
confirm this Agreement and agree that it shall bind my interest in the Shares,
if any.




                                   ------------------------------------------
                                         (Shareholder's Spouse's Name)


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