Exhibit 99.1

                        Southern Financial Bancorp, Inc.
               Proxy Solicited on Behalf of the Board of Directors


         The    undersigned    hereby    appoints    ____________________    and
____________________,  jointly and  severally,  proxies,  with full power to act
alone, and with full power of substitution,  to represent the undersigned and to
vote, as  designated  below and upon any and all other matters that may properly
be brought before such meeting,  all shares of Common Stock that the undersigned
would be  entitled  to vote at a Special  Meeting of  Shareholders  of  Southern
Financial  Bancorp,  Inc. (the "Company") to be held at Fauquier Springs Country
Club,  Springs  Road,  Warrenton,  Virginia,  on ________ __, 1999 at 2:00 p.m.,
local time, or any adjournments thereof, for the following purposes:

         1.       To approve the issuance of Common Stock to the shareholders of
                  The Horizon Bank of Virginia  ("Horizon")  in connection  with
                  the Agreement and Plan of  Reorganization,  dated as of May 3,
                  1999,  as  amended,  by and between  Horizon,  the Company and
                  Southern  Financial  Bank (the "Bank"),  and a related Plan of
                  Merger,  which provides for Horizon to be merged with and into
                  the Bank.  The  Reorganization  Agreement is enclosed with the
                  accompanying Joint Proxy Statement as Appendix A.

                      [    ]  FOR       [    ]  AGAINST          [    ]  ABSTAIN


         2.       To  elect  as  directors  the three persons listed as nominees
                  below.


                                                                
                  [    ]  FOR nominees listed below                [    ]  WITHHOLD AUTHORITY to
                          (except as written on the line below)            vote for all nominees listed below




                                                                                 
                    For Term Expiring in 2000         For Term Expiring in 2001        For Term Expiring in 2002

                         John C. Belotti                   Richard L. Hall                Robert P. Warhurst



                           (INSTRUCTION:  To withhold  authority to vote for any
                  individual nominee listed above, write that nominee's  name on
                  the space provided below.)

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

         3.       In their  discretion,  the proxies are authorized to vote upon
                  any other  business that may properly come before the meeting,
                  or any adjournment thereof.


         THIS  PROXY,  WHEN  PROPERLY  EXECUTED,  WILL BE  VOTED  IN THE  MANNER
DIRECTED HEREIN BY THE SHAREHOLDER. IF NO DIRECTION IS GIVEN, THIS PROXY WILL BE
VOTED FOR ITEM 1 AND FOR ALL NOMINEES LISTED IN ITEM 2.


- ---------------------------------       ---------------------------------------
         Printed Name                                    Signature


                                        ---------------------------------------
                                                         Signature

                                        Dated:   ___/___/99

                                        (If  signing as Attorney, Administrator,
                                        Executor, Guardian or  Trustee,  please
                                        add  your  title  as such.)

                   PLEASE MARK, SIGN, DATE AND RETURN PROMPTLY