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                                                                       EXHIBIT 5


               [FOSTER, SWIFT, COLLINS & SMITH, P.C. LETTERHEAD]



June 22, 1999

Commercial National
   Financial Corporation
101 North Pine River
Ithaca, MI 48847

Dear Gentlemen:

Re:      Commercial National Financial Corporation
         Registration Statement on Form S-3

You have requested our opinion as counsel to Commercial National Financial
Corporation, a Michigan corporation, in connection with a Registration Statement
filed with the Securities and Exchange Commission under the Securities Act of
1933, as amended, on Form S-3. The Registration Statement relates to the
offering of an additional 50,000 shares of Commercial National Financial
Corporation common stock to be issued to stockholders in connection with the
Commercial National Financial Corporation Dividend Reinvestment Plan.

Based upon such examination and upon examination of such other instruments and
records as we deem necessary, we are of the opinion that:

1.       The Corporation has been duly incorporated under the laws of the State
         of Michigan, and is validly existing and in good standing under the
         laws of that state.
2.       The 50,000 shares of common stock covered by this Registration
         Statement have been legally authorized; and when such shares have been
         duly delivered to stockholders against payment therefore as
         contemplated by the Commercial National Financial Corporation Dividend
         Reinvestment Plan, such shares will be legally issued, fully paid and
         nonassessable.

This opinion is furnished for use as an Exhibit to the Registration Statement.
We hereby consent to the filing of this opinion as an Exhibit to the
Registration Statement.

FOSTER, SWIFT, COLLINS & SMITH, P.C.


/s/ Foster, Swift, Collins & Smith, P.C.