Exhibit 99.1 News Release FIRST FINANCIAL CORPORATION One First Financial Plaza, Terre Haute, Indiana 47807 (812) 238-6000 First Financial Corporation Reports Third Quarter Results Terre Haute, Indiana, October 28, 2025 – First Financial Corporation (NASDAQ:THFF) today announced results for the third quarter of 2025. The Corporation further reported results for the nine months ended September 30, 2025: 1 Non-GAAP financial measure that Management believes is useful for investors and management to understand ...