UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549
                              ------------------
Mark One                           FORM 10-K/A
                               (Amendment No. 1)      

[X]  ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
     ACT OF 1934

For the fiscal year ended December 31, 1998

[_]  TRANSITIONAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934

For the transition period from_____to_____                

                        Commission File Number: 0-18279
                                               --------- 

                        TRI-COUNTY FINANCIAL CORPORATION
         --------------------------------------------------------------
             (Exact name of registrant as specified in its charter)

                  Maryland                                  52-1652138      
- --------------------------------------                   ------------------ 
(State or other jurisdiction of incorporation             (I.R.S. Employer
or organization)                                         Identification No.)

3035 Leonardtown Road, Waldorf, Maryland                       20601   
- ----------------------------------------                     --------
(Address of principal executive offices)                     Zip Code

Registrant's telephone number, including area code  (301) 645-5601  
                                                   ----------------

Securities registered pursuant to Section 12(b) of the Act:  None
                                                             ----

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

                     Common Stock, par value $.01 per share
                     --------------------------------------
                                (Title of Class)

     Indicate by check mark whether the registrant (l) 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
                                              ---    ---

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of 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. 

     As of March 22, 1999, there were issued and outstanding 793,563 shares of
the registrant's common stock.

     The registrant's voting stock is not regularly and actively traded in any
established market and there are no regularly quoted bid and asked prices for
the registrant's common stock. The registrant believes the approximate trading
price for the stock to be $24.31 per share for an approximate aggregate market
value of voting stock held by non-affiliates of the registrant of $14.3 million.
For purposes of this calculation, the shares held by directors and executive
officers of the registrant and by any stockholder beneficially owning more than
5% of the registrant's outstanding common stock are deemed to be shares held by
affiliates.

                      DOCUMENTS INCORPORATED BY REFERENCE

1.   Portions of Annual Report to Stockholders for the Fiscal Year Ended
     December 31, 1998. (Parts I and II)

2.   Portions of Proxy Statement for the 1999 Annual Meeting of Stockholders.
     (Part III)


 
                                   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.

                        TRI-COUNTY FINANCIAL CORPORATION

    
Date: April 13, 1999                By:  /s/ Michael L. Middleton      
                                         -------------------------------------
                                           Michael L. Middleton                 
                                           President and Chief Executive Officer
                                           (Duly Authorized Representative)
    
Date: April 13, 1999              By: /s/ Eileen M. Ramos                
                                      ----------------------------------------
                                        Eileen M. Ramos
                                        Chief Financial Officer
                                        (Duly Authorized Representative)

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

     

                                                 
By:  /s/ Michael L. Middleton                   By:   /s/ Herbert N. Redmond, Jr. 
     --------------------------------------           ----------------------------
     Michael L. Middleton                             Herbert N. Redmond, Jr.
     (Director, President and Chief                   (Director)
     Executive Officer)

Date: April 13, 1999                            Date: April 13, 1999



By:  /s/ Henry A. Shorter, Jr.                  By:   /s/ W. Edelen Gough, Jr.    
     --------------------------------------           ----------------------------
     Henry A. Shorter, Jr.                            W. Edelen Gough, Jr.
     (Director)                                       (Director)

Date: April 13, 1999                            Date: April 13, 1999



By:  /s/ C. Marie Brown                         By:   /s/ Gordon A. O'Neill       
     --------------------------------------           ----------------------------
     C. Marie Brown                                   Gordon A. O'Neill
     (Director and Chief Operating Officer)           (Director)

Date: April 13, 1999                            Date: April 13, 1999



By:  /s/ Beaman Smith               
     --------------------------------------
     Beaman Smith
     (Director and Secretary/Treasurer)

Date: April 13, 1999
      

                                       29