Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 2019 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___________________ to __________________ Commission File Number 001-31303 BLACK HILLS CORPORATION Incorporated in South Dakota IRS Identification Number 46-0 ...