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☑ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Indiana Commission file number 0-16759 FIRST FINANCIAL CORPORATION ( Exact name of registrant as specified in its charter ) ( State of Incorporation ) One First Financial Plaza Terre Haute , Indiana ( Address of Registrant's Principal Executive Offices ) ( 812 ) 238-6000 35-1546989 ( I.R.S. Employer Identification Number ) 47807 ( Zip Code ) ( Registrant's Telephone Number , Including Area Code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol THFF Name of each exchange on which registered The NASDAQ Stock Market LLC Securities registered pursuant to Section 12 ( g ) of the Act : Title of each class Common Stock , par value $ 0.125 per share None No ☑ Indicate by check mark if the registrant is a well - known - seasoned issuer , as defined in Rule 405 of the Securities Act . Yes ☐ Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes No ✓ 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 required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes ☑ No □ Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site , if any , every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S - T ( § 232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit and post such files ) . Yes No □ Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S - K is not contained herein , and will not be contained , to the best of registrant's knowledge , in definitive proxy or information statements incorporated by reference in Part III of this Form 10 - K or any amendment to this Form 10 - K .