UNITED
STATES

SECURITIES
AND EXCHANGE COMMISSION

Washington,
D.C. 20549



FORM
10-K/A

(Amendment No. 1)



xANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

|For the
                                         fiscal year ended | December 31, 2017
|------------------------------------------------------------------ | -----------------
|                                                                   |                  

or

oTRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period
from __________________________ to ______________________________ ________

Commission File No. 0-31525

AMERICAN
RIVER BANKSHARES




(Exact
name of registrant as specified in its charter)



|California                     |  | 68-0352144                       
|------------------------------ |  | ---------------------------------
|State or other jurisdiction of |  | (IRS Employer Identification No.)
|incorporation or organization  |  |                                  



|3100 Zinfandel Drive, Rancho Cordova, California | 95670     
|------------------------------------------------ | ----------
|(Address of principal executive offices)         | (Zip code)
|                                                 |           

Registrant’s telephone number, including
area code 916-851-0123



Securities registered pursuant to
Section 12(b) of the Act:





|Title
    of Each Class        |  | Name
    of Each Exchange On Which Registered
|------------------------------ |  | ---------------------------------------------
|Common
    Stock, no par value |  | NASDAQ
    Global Select Market              



|Securities
    registered pursuant to Section 12(g) of the Act:
|---------------------------------------------------------------

None





Indicate by check mark if the registrant
is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.

Yes o No
x



Indicate by check mark if the registrant
is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.

Yes o No x



Indicate by check mark whether the
registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject
to such filing requirements for the past 90 days.

Yes x No o



Indicate by
check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive
Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T(§232.405 of this chapter) during the
preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).

Yes x No o



Indicate by check mark if
disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein,
and will not be contained, to the best of the registrant’s knowledge, in definitive proxy or information statements incorporated
by reference in Part III of this Form 10-K or any amendment to this Form 10-K.   x

Indicate
by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller
reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller
reporting company” in Rule 12b-2 of the Exchange Act.



|Large accelerated filer o                                             | Accelerated filer x        
|--------------------------------------------------------------------- | ---------------------------
|Non-accelerated filer o (Do not check if a smaller reporting company) | Smaller reporting company o
|                                                                      | Emerging growth company o  



If an emerging
growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with
any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o



Indicate by
check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes o No x



State the aggregate market value
of the voting and non-voting common equity held by non-affiliates computed by reference to the price at which the common equity
was last sold, or the average bid and asked price of such common equity, as of the last business day of the registrant’s
most recently completed second fiscal quarter. $88,881,000.



Indicate the
number of shares outstanding of each of the registrant’s classes of common stock, as of the latest practicable date.



As of
February 26, 2018, the registrant’s no par value Common Stock totaled 6,050,924 shares outstanding.







EXPLANATORY
NOTE



The sole
purpose of this Amendment No. 1 (the “Amendment”) to American River Bankshares Annual Report on Form 10-K (the
“Form 10-K”) for the Period ended December 31, 2017, as filed with the Securities and Exchange Commission on
February 28, 2018, is to revise the hyperlink in Exhibit 10.3 in Item 15.



The revised hyperlink in Exhibit 10.3 is for the
first amendment thereto dated January 21, 2015, incorporated by reference from Exhibit 99.1 to the Registrant's Current
Report on Form 8-K, filed with the Commission on January 23, 2015.  This Amendment contains only the cover page to this Form
10-K/A, the Explanatory Note, Item 15, the Signature Page and the Sarbanes-Oxley Exhibits.  No other changes have been made
to the Form 10-K.



This Amendment to the Form 10-K does not reflect events that may have occurred subsequent to the original
filing date and does not modify or update in any way disclosures made in the original Form 10-K. Accordingly, this Amendment
should be read in conjunction with the Form 10-K and our other filings with the SEC.

2





Item 15. Exhibits and Financial
Statement Schedules.



|    |               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|--- | ------------- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|(a) | (3) Exhibits.
|    |               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|    | ExhibitNumber | Document
                                         Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|    |               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|    | *(10.3)       | Registrant’s
                                         Deferred Compensation Plan, incorporated by reference from Exhibit 99.1 to the Registrant’s
                                         Current Report on Form 8-K, filed with the Commission on January 3, 2012 and first amendment
                                         thereto dated January 21, 2015, incorporated by reference from Exhibit 99.1 to the 	Registrant’s
                                         Current Report on Form 8-K, filed with the Commission on January 23, 2015.

| |  | * Denotes
management contracts, compensatory plans or arrangements.
| |  | -------------------------------------------------------------------



3





SIGNATURES

Pursuant
to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report
to be signed on its behalf by the undersigned, thereunto duly authorized.

|                                                                                                                 |                                                 
|---------------------------------------------------------------------------------------------------------------- | ------------------------------------------------
|                                                                                                                 | AMERICAN RIVER BANKSHARES                       
|                                                                                                                 |                                                 
|November 7,
                                                                                                2018 | By:
    /s/ DAVID E. RITCHIE, JR.               
|                                                                                                                 | David E. Ritchie, Jr.                           
|                                                                                                                 | Chief Executive Officer                         
|                                                                                                                 | (Principal Executive
    Officer)               
|                                                                                                                 |                                                 
|November 7, 2018                                                                                                 | By:
    /s/ MITCHELL A. DERENZO                 
|                                                                                                                 | Mitchell A. Derenzo                             
|                                                                                                                 | Chief Financial Officer                         
|                                                                                                                 | (Principal Financial
    and Accounting Officer)



Pursuant
to the requirements of the Securities and Exchange Act of 1934, this report has been signed below by the following persons on
behalf of the registrant in the capacities and on the dates indicated.

|                                                             |  |                                                  |  |         
|------------------------------------------------------------ |  | ------------------------------------------------ |  | --------
|Signature                                                    |  | Title                                            |  | Date    
|                                                             |  |                                                  |  |         
|/s/
    KIMBERLY A.BOX                                       |  | Director                                         |  | 10/28/18
|Kimberly
    A. Box                                          |  |                                                  |  |         
|                                                             |  |                                                  |  |         
|/s/
    CHARLES D. FITE                                      |  | Director,
    Chairman                           |  | 11/07/18
|Charles
    D. Fite                                          |  |                                                  |  |         
|                                                             |  |                                                  |  |         
|/s/
                                         JEFFERY OWENSBY |  | Director                                         |  | 10/26/18
|Jeffery
                                         Owensby     |  |                                                  |  |         
|                                                             |  |                                                  |  |         
|/s/
    DAVID  E. RITCHIE, JR.                               |  | Director,
    Chief Executive Officer            |  | 11/07/18
|David E. Ritchie,
    Jr.                                    |  | (Principal Executive
    Officer)                |  |         
|                                                             |  |                                                  |  |         
|/s/
    STEPHEN H. WAKS                                      |  | Director                                         |  | 10/25/18
|Stephen
    H. Waks                                          |  |                                                  |  |         
|                                                             |  |                                                  |  |         
|/s/
    PHILIP A. WRIGHT                                     |  | Director                                         |  | 10/29/18
|Philip
    A. Wright                                         |  |                                                  |  |         
|                                                             |  |                                                  |  |         
|/s/
    MICHAEL A. ZIEGLER                                   |  | Director                                         |  | 10/25/18
|Michael A. Ziegler                                           |  |                                                  |  |         
|                                                             |  |                                                  |  |         
|/s/
    MITCHELL A. DERENZO                                  |  | Chief
    Financial Officer                      |  | 11/07/18
|Mitchell
    A. Derenzo                                      |  | (Principal
    Financial and Accounting Officer) |  |         

4





EXHIBIT
INDEX

|Exhibit
    Number | Description                                                                                                                                                  |  | Page
|------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------ |  | ----
|                   |                                                                                                                                                              |  |     
|                   |                                                                                                                                                              |  |     
|31.1               | Certifications of Chief
    Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002                                                      |  | 6   
|                   |                                                                                                                                                              |  |     
|31.2               | Certifications of Chief
    Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002                                                      |  | 7   
|                   |                                                                                                                                                              |  |     
|32.1               | Certification of American River Bankshares
    Chief Executive Officer and Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 |  | 8   

5