EXHIBIT 16 - LETTER REGARDING CHANGE IN CERTIFYING ACCOUNTANT March 21, 1997 Securities and Exchange Commission 450 Fifth Street N.W. Washington, DC 20549 Gentlemen: We have read Item 9 of this Annual Report on Form 10-K for the fiscal year ended December 31, 1996, of Tompkins County Trustco, Inc. and are in agreement with the statements contained in paragraphs 1 through 3 on page 14 therein. /S/ Ernst & Young LLP Syracuse, New York March 21, 1997