<ACCESSION-NUMBER>0001130464-18-000026 <TYPE>8-K <PUBLIC-DOCUMENT-COUNT>3 <PERIOD>20180503 <ITEMS>2.02 <ITEMS>9.01 <FILING-DATE>20180504 <DATE-OF-FILING-DATE-CHANGE>20180503 <FILER> <COMPANY-DATA> <CONFORMED-NAME>BLACK HILLS CORP /SD/ <CIK>0001130464 <ASSIGNED-SIC>4911 <IRS-NUMBER>460458824 <STATE-OF-INCORPORATION>SD <FISCAL-YEAR-END>1231 </COMPANY-DATA> <FILING-VALUES> <FORM-TYPE>8-K <ACT>34 <FILE-NUMBER>001-31303 <FILM-NUMBER>18805386 </FILING-VALUES> <BUSINESS-ADDRESS> <STREET1>7001 MT RUSHMORE RD <STREET2>PO BOX 1400 <CITY>RAPID CITY <STATE>SD <ZIP>57709 <PHONE>6057212343 </BUSINESS-ADDRESS> <MAIL-ADDRESS> <STREET1>7001 MT RUSHMORE RD <STREET2>PO BOX 1400 <CITY>RAPID <STATE>SD <ZIP>57709 </MAIL-ADDRESS> <FORMER-COMPANY> <FORMER-CONFORMED-NAME>BLACK HILLS HOLDING CORP <DATE-CHANGED>20001222 </FORMER-COMPANY> </FILER>