<PAGE>   1

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C 20549

          _x_      QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF
                      THE SECURITIES EXCHANGE ACT OF 1934
                    For the Quarter Ended September 30, 1997
                    Commission file number: 0-17482

          ___    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(D) OF
                      THE SECURITIES EXCHANGE ACT OF 1934
                 For the transition period from______ to______


                                County Bank Corp
                           Michigan   EIN 38-0746239
                     83 W. Nepessing St., Lapeer, MI 48446
                                 (810) 664-2977


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 re- quired to file such reports), and (2) has been subject to
such filing requirements for the past 90 days.

Yes__X__  No_____



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

There are 593,236 shares of common stock ($5.00 par value) outstanding  as of
September 30, 1997.




<PAGE>   2
                                COUNTY BANK CORP

                                   FORM 10-Q

                    For the Quarter Ended September 30, 1997

                                     INDEX


<TABLE>
<CAPTION>
PART I: FINANCIAL INFORMATION                                                                 PAGE
<S>                                                                                           <C>
                                                                                              
     Item 1.  Financial Statements                                                              2
          . Introduction-                                                                     
                                                                                              
          . Balance Sheets -                                                                    3
          At September 30, 1997 and December 31, 1996                                         
                                                                                              
          . Statements of Income -                                                              4
          For the three months and six months ended September 30, 1997 and 1996               
                                                                                              
          . Statement of Cash Flows -                                                           5
          For the three months and six months ended September 30, 1997 and 1996               
                                                                                              
     Item 2.  Management's Discussion and Analysis of                                           6
          Financial Condition and Results of Operations                                       
                                                                                              
PART II: OTHER INFORMATION                                                                    
                                                                                              
    Item 6. Exhibits and Reports on Form 8-K                                                    7
                                                                                              
                                                                                              
All items exept those set forth above are inapplicable and have been omitted.                 
                                                                                              
                                                                                              
SIGNATURES                                                                                      8
</TABLE>



<PAGE>   3
Part I - Financial Information

Item I - Financial Statements

Introduction to Financial Statements

The consolidated financial statements of County Bank Corp and subsidiary,
Lapeer County Bank & Trust Co., have been prepared, without audit, pursuant to
the rules and regulations of the Securities and Exchange Commission.  Certain
information and footnote disclosures normally included in financial statements
prepared in accordance with generally accepted accounting principles have been
omitted pursuant to such rules and regulations.  The Company believes that the
disclosures are adequate to make the information presented not misleading when
read in conjunction with financial statements and the notes thereto included in
County Bank Corp's Form 10-K as filed with the Securities and Exchange
Commission for the year ended December 31, 1996.

The financial information presented reflects all adjustments (consisting only
of normal recurring adjustments) which are, in the opinion of mangement,
necessary for a fair statement of the results for the interim periods
presented.  The results for interim periods are not necessarily indicative of
the results to be expected for the year.








                                                                        Page 2
<PAGE>   4
<TABLE>
<CAPTION>
CONSOLIDATED STATEMENTS
BALANCE SHEETS (in thousands)                                                SEPT 30         DECEMBER 31
                                                                               1997             1996
<S>                                                                          <C>                <C>
ASSETS                                                                  
Cash and due from banks.................................................       8,096              8,626
Investment securities available for sale................................      16,837             19,330
Investment securities held to maturity..................................      29,634             28,079
                                                                             -------            -------
    Total investment securities.........................................      46,471             47,409
Federal funds sold .....................................................       4,700              1,200
Loans...................................................................     119,526            117,474
   Less: Reserve for possible loan losses...............................       1,922              1,805
                                                                             -------            -------
      Net loans.........................................................     117,604            115,669
Bank premises & equipment...............................................       2,701              2,715
Interest receivable and other assets....................................       2,468              2,167
                                                                             -------            -------
   TOTAL ASSETS.........................................................     182,040            177,786
                                                                             =======            =======
LIABILITIES & STOCKHOLDERS' EQUITY                                      
                                                                        
                                                                        
LIABILITIES                                                             
Deposits:                                                               
   Demand...............................................................      69,646             68,614
   Savings..............................................................      40,670             41,292
   Time ................................................................      47,984             46,612
                                                                             -------            -------
     Total deposits.....................................................     158,300            156,518
Interest payable and other liabilities..................................       1,750              1,406
                                                                             -------            -------
                                                                        
   TOTAL LIABILITIES....................................................     160,050            157,924
STOCKHOLDERS' EQUITY                                                    
                                                                        
Common stock-$5.00 par value, 1,200,000 shares authorized and           
 593,236 shares outstanding in 1996 and 1997............................       2,966              2,966
Surplus.................................................................       8,634              8,634
Undivided profits.......................................................       9,687              7,882
Unrealized gains on securities available for sale                                703                380
                                                                             -------            -------
   TOTAL STOCKHOLDERS' EQUITY...........................................      21,990             19,862
                                                                             -------            -------
   TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY...........................     182,040            177,786
                                                                             =======            =======
</TABLE>



                                                                        Page 3
<PAGE>   5
<TABLE>
<CAPTION>
STATEMENT OF CASH FLOWS                                                THREE MONTHS ENDED           NINE MONTHS ENDED
(in thousands)                                                            SEPTEMBER 30                SEPTEMBER 30
                                                                        1997       1996              1997       1996
<S>                                                                    <C>        <C>               <C>        <C>          
Cash flows from operating activities                                                                                        
Net income.........................................................       764        730             2,303      2,205       
Adjustments to reconcile net income to net                                                                                  
  cash provided from operating activities:                                                                                  
Depreciation and amortization......................................        61         61               326        276       
Provision for loan losses..........................................        30         30                90         90       
Net amortization and accretion of securities.......................      (138)        14               (42)       148       
Deferred income taxes..............................................         0          0                 0          0       
Net gain on sale of investment securities..........................         0          0                 0          0       
(Gain) loss on other real estate owned.............................       (24)        (5)              (37)       (12)      
Net change in accrued interest receivable..........................      (207)      (209)             (355)      (323)      
Net change in accrued interest payable and other...................       469        (63)              344         74       
                                                                       ------     ------            ------     ------
                                                                                                                            
Net cash provided by operating activities..........................       955        558             2,629      2,458       
                                                                       ------     ------            ------     ------
Cash flows from investing activities                                                                                        
Proceeds from sale of investment securities: AFS...................         0          0                 0          0       
Proceeds from maturities of investment securities: AFS.............     1,526         72             4,538      1,755       
Proceeds from maturities of investment securities: HTM.............       196      2,060             2,101      5,974       
Purchase of investment securities: AFS.............................    (1,267)      (195)           (1,592)    (4,215)      
Purchase of investment securities: HTM.............................    (1,388)    (1,499)           (3,755)    (2,833)      
Net (increase) decrease in loans...................................      (263)    (6,113)           (2,081)    (9,985)      
Proceeds from the sale of Other Real Estate........................        93         54               180        278       
Premises and equipment expenditures................................      (250)       (29)             (334)      (282)      
                                                                       ------     ------            ------     ------
                                                                                                                            
Net Cash provided from (used in) investing activities                  (1,353)    (5,650)             (943)    (9,308)      
                                                                       ------     ------            ------     ------
Cash flows from financing activities                                                                                        
Net increase (decrease) in interest bearing                                                                                 
  and non-interest bearing demand accounts.........................        19        907             1,032      5,251       
Net increase (decrease) in savings and time deposits...............       718       (297)              750     (2,068)      
Cash dividends paid................................................      (166)      (148)             (498)      (445)      
                                                                       ------     ------            ------     ------
                                                                                                                            
Net Cash provided from (used in)financing activities...............       571        462             1,284      2,738       
                                                                       ------     ------            ------     ------
                                                                                                                            
Net increase (decrease) in cash and equivalents....................       173     (4,630)            2,970     (4,112)      
Cash and equivalents at beginning of year                              12,623     13,595             9,826     13,077       
                                                                       ------     ------            ------     ------
Cash and equivalents at end of period                                  12,796      8,965            12,796      8,965       
                                                                       ======     ======            ======     ======
Cash paid for:                                                                                                              
Interest...........................................................     1,291      1,223             3,855      3,583       
Income taxes.......................................................       334        408               914        890       
</TABLE>


                                                                        Page 5
<PAGE>   6
<TABLE>
<CAPTION>
CONSOLIDATED INCOME STATEMENTS
(in thousands)                                                  THREE MONTHS             FOR THE NINE MONTHS
                                                                   ENDED                        ENDED
                                                                SEPTEMBER 30                 SEPTEMBER 30
INTEREST INCOME                                               1997        1996             1997        1996
<S>                                                           <C>         <C>             <C>          <C>
Interest and fees on loans.............................       2,658       2,441            7,795       7,077
Interest on investment securities:                              693         723            2,106       2,090
Interest on Federal funds sold.........................          67          49              214         200
                                                              -----       -----           ------       -----
      TOTAL INTEREST INCOME............................       3,418       3,213           10,115       9,367
INTEREST EXPENSE                                                                          
   Demand deposits.....................................         354         319            1,034         881
   Savings deposits....................................         305         305              968         918
   Time deposits.......................................         632         599            1,851       1,783
   Borrowed funds......................................           0           0                2           1
                                                              -----       -----           ------       -----
      TOTAL INTEREST EXPENSE...........................       1,291       1,223            3,855       3,583
                                                              -----       -----           ------       -----
NET INTEREST INCOME....................................       2,127       1,990            6,260       5,784
Provision for possible loan losses.....................          30          30               90          90
NET INTEREST INCOME AFTER                                                                 
   PROVISION FOR LOAN LOSSES...........................       2,097       1,960            6,170       5,694
OTHER INCOME                                                                              
Service fees on loan and deposit accounts..............         276         281              819         846
Other..................................................         257         207              716         833
                                                              -----       -----           ------       -----
      TOTAL OTHER INCOME...............................         533         488            1,535       1,679
OTHER EXPENSES                                                                            
Salaries and employee benefits.........................         901         857            2,642       2,586
Net occupancy expense..................................         245         189              677         574
Other..................................................         425         395            1,202       1,158
                                                              -----       -----           ------       -----
      TOTAL OTHER EXPENSE..............................       1,571       1,441            4,521       4,318
                                                              -----       -----           ------       -----
                                                                                          
INCOME BEFORE PROVISION FOR                                                               
   FEDERAL INCOME TAX..................................       1,059       1,007            3,184       3,055
Provision for Federal income tax.......................         295         277              881         850
                                                              -----       -----           ------       -----
NET INCOME.............................................         764         730            2,303       2,205
                                                              =====       =====           ======       =====   
EARNINGS PER SHARE                                                                        
Net Income.............................................       $1.29       $1.23            $3.88       $3.72
Cash Dividend Declared.................................       $0.28       $0.25            $0.84       $0.75
</TABLE>




                                                                        Page 4
<PAGE>   7
Item 2.  Management's Discussion and Analysis of Financial Condition and the
Results of Operations.

Financial Condition

New loan production continued through the third quarter of 1997, but on a
slower pace than the second quarter and first quarter produced.  New loan
production has declined in each quarter.  Net increases in loans totaled
$2,081,000 year to date in 1997.  Net increases in deposits for both interest
bearing and non-interest bearing demand deposits totaled 19,000 for the quarter
and totaled $1,032,000 for the year.  Time and savings deposits increased
$718,000 during the quarter.  Year to date increased in Time and savings
deposits totaled $750,000.  Moderate deposit growth is characteristic of the
Corporation's market.

Loan demand was met with cash provided deposit growth.  Income from operations
and net decreases in the investment portfolio resulted in net increases to cash
and cash equivalents.  Management expects continued loan growth during the
fourth quarter and is remaining liquid to meet the demand from loan customers.

Results of Operations

Net income per share for the quarter was $1.29 resulting in year to date
earnings per share of $3.88.  The growth in loans was the primary contributor
to increased interest income.  Non interest income and expense categories
remained at levels consistent with the Corporation's recent performance.

Risk Factors

Loan quality remains high.  The reserve for loan losses to gross loans ratio is
1.61%.  The non performing loans to total loans ratios is .78%.  This ratio
compares loans past due 90 days or more and loans in non-accrual status to
total loans.  This is an historically low ratio and indicates a high quality
portfolio.

The Corporation remains liability sensitive in relation to the risk of changes
in interest rates.  The demand for residential mortgages remains strong in the
market area.  Options to maintain both repricing opportunities for assets and
market tendencies for deposits are under constant review.

Capital

Strong net income performance and conservative dividend payments result in
increased capital.  The moderate growth results in improving capital ratios.



                                                                Page 6
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Part II.

Item 6.  Exhibits and Reports on Form 8-K.

      A) Not Applicable

      B) A Form 8-K has not been filed during the six months ended 
         September 30, 1997.


















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                                 SIGNATURES

Pursuant to the requirements 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.

                                        COUNTY BANK CORP
Date November 11, 1997
                                        /s/ Joseph H. Black
                                        ---------------------------------
                                        Joseph H. Black, Treasurer















                                                                        Page 8
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                              INDEX TO EXHIBITS



EXHIBIT NO.                     DESCRIPTION
-----------                     -----------

  EX-27                         Financial Data Schedule