EXHIBIT 10.21 AMENDMENT #1 TO OFFICE BUILDING LEASE DATED JUNE 29, 1999 BY AND BETWEEN UNION BANK OF CALIFORNIA, N.A., AS TRUSTEE FOR AGNES M. BOURN AND WILLIAM B. BOURN ("LANDLORD") AND FIRST SOURCE CAPITAL, WHOLLY OWNED SUBSIDIARY OF AMERICAN RIVER HOLDINGS ("TENANT"). This Addendum is hereby made a part of that certain Office Building lease between the above-mentioned parties dated June 29, 1999 (the "Contract"). Said document shall hereby be amended as follows. In the event of any discrepancy between this document and any previous document(s) the provisions of this document shall prevail. 2.d. COMMENCEMENT DATE: March 1, 2001 2.g. EXPIRATION DATE: February 28, 2002 2.j MONTHLY BASE RENT: March 1, 2001 to February 28, 2002 @ $1,270.50 2.l. PREMISES: Tenant is relocating from 1540 River Park Drive, Suite 108 (381 Square feet) to 1540 River Park Drive, Suite 106 that portion of the building containing approximately 847 square feet of Rentable Area located on the first floor. 2.r. PROPORTIONATE SHARE: 1.13% 3. TENANT IMPROVEMENTS: Landlord at Landlord's sole cost to complete the following tenant improvements: 1) Paint entire suite with upgraded semi-gloss paint. 2) Professionally clean carpets. CONSULT YOUR ADVISORS - This document (including its exhibits and addendums, if any) has been prepared by Broker for approval by the undersigned respective parties legal counsel. Broker makes no representation or recommendation as to the legal sufficiency or tax consequences of this document or the transaction to which it relates. These are questions for an attorney or accountant. 124 THE ABOVE TERMS ARE ACKNOWLEDGED AND AGREED TO: LANDLORD TENANT Union Bank of California, N.A., as trustee First Source Capital, wholly for Agnes M. Bourn and William B. Bourn Trust owned Subsidiary of American River Holdings Corporation By: /s/ BRIAN T. MULLINS By: /s/ DAVID T. TABER -------------------- ---------------------- Brian T. Mullins, Vice President David T. Taber Its: Vice President Its: CEO Date: 2/27/01 Date: 3/1/01 125