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( Mark One ) ☑ 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 Commission file number 001-09712 to uscellular UNITED STATES CELLULAR CORPORATION ( Exact name of Registrant as specified in its charter ) Delaware ( State or other jurisdiction of incorporation or organization ) 62-1147325 ( IRS Employer Identification No. ) 8410 West Bryn Mawr , Chicago , Illinois 60631 ( Address of principal executive offices ) ( Zip code ) Registrant's telephone number , including area code : ( 773 ) 399-8900 7.25 % Senior Notes Due 2063 7.25 % Senior Notes Due 2064 6.25 % Senior Notes Due 2069 5.50 % Senior Notes Due 2070 Securities registered pursuant to Section 12 ( b ) of the Act : Title of each class Common Shares , $ 1 par value 6.95 % Senior Notes Due 2060 Trading Symbol USM UZA Name of each exchange on which registered New York Stock Exchange New York Stock Exchange UZB New York Stock Exchange UZC New York Stock Exchange UZD New York Stock Exchange UZE New York Stock Exchange Securities registered pursuant to Section 12 ( g ) of the Act : None Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes No ☑ Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Exchange Act . Yes ☐ No ☑ Yes 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 . Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes ☑ ☑ No NNNN No ☐ ☐