<TABLE> <S> <C>

<PAGE>
 
<ARTICLE> 9
<MULTIPLIER> 1,000
       
<S>                             <C>                     <C>
<PERIOD-TYPE>                   9-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998             DEC-31-1997
<PERIOD-START>                             JAN-01-1998             JAN-01-1997
<PERIOD-END>                               SEP-30-1998             SEP-30-1997
<CASH>                                          16,307                  20,166
<INT-BEARING-DEPOSITS>                             105                     200
<FED-FUNDS-SOLD>                                     0                       0
<TRADING-ASSETS>                                     0                       0
<INVESTMENTS-HELD-FOR-SALE>                    305,237                 222,411
<INVESTMENTS-CARRYING>                               0                       0
<INVESTMENTS-MARKET>                                 0                       0
<LOANS>                                        675,557                 670,317
<ALLOWANCE>                                     (8,908)                 (6,995)
<TOTAL-ASSETS>                               1,022,285                 929,990
<DEPOSITS>                                     760,387                 720,785
<SHORT-TERM>                                   114,800                  89,500
<LIABILITIES-OTHER>                             21,536                  13,792
<LONG-TERM>                                     77,919                  53,548
<PREFERRED-MANDATORY>                                0                       0
<PREFERRED>                                          0                       0
<COMMON>                                         1,250                   1,377
<OTHER-SE>                                      46,393                  50,988
<TOTAL-LIABILITIES-AND-EQUITY>               1,022,285                 929,990
<INTEREST-LOAN>                                 51,551                  49,364
<INTEREST-INVEST>                               10,048                   6,555
<INTEREST-OTHER>                                   358                     402
<INTEREST-TOTAL>                                61,957                  56,321
<INTEREST-DEPOSIT>                              28,654                  28,159
<INTEREST-EXPENSE>                              38,335                  35,417
<INTEREST-INCOME-NET>                           23,622                  20,904
<LOAN-LOSSES>                                    3,067                   2,160
<SECURITIES-GAINS>                               8,362                   2,204
<EXPENSE-OTHER>                                 35,462                  19,737
<INCOME-PRETAX>                                  9,919                   8,204
<INCOME-PRE-EXTRAORDINARY>                       9,919                   8,204
<EXTRAORDINARY>                                      0                       0
<CHANGES>                                            0                       0
<NET-INCOME>                                     5,784                   4,421
<EPS-PRIMARY>                                     4.25                    3.21
<EPS-DILUTED>                                     4.25                    3.21
<YIELD-ACTUAL>                                    3.31                    3.27
<LOANS-NON>                                      7,318                   5,682
<LOANS-PAST>                                         0                       0
<LOANS-TROUBLED>                                 2,020                   2,067
<LOANS-PROBLEM>                                  9,338                   7,749
<ALLOWANCE-OPEN>                                 7,333                   5,904
<CHARGE-OFFS>                                    2,233                   1,564
<RECOVERIES>                                       741                     495
<ALLOWANCE-CLOSE>                                8,908                   6,995
<ALLOWANCE-DOMESTIC>                                 0                       0
<ALLOWANCE-FOREIGN>                                  0                       0
<ALLOWANCE-UNALLOCATED>                              0                       0
        

</TABLE>