Exhibit 99.1

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FOR IMMEDIATE RELEASE

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For more information contact:

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March 18, 2026

Rodger A. McHargue at (812) 238-6000

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First Financial Corporation Declares Quarterly Dividend

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TERRE HAUTE, INDIANA - The directors of First Financial Corporation (NASDAQ: THFF) have declared a dividend of 56 cents per share payable on April 15, 2026, to shareholders of record at the close of business April 1, 2026.

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First Financial Corporation is the holding company for First Financial Bank N.A. in Indiana, Illinois, Kentucky, Tennessee, and Georgia.