海角涩区

Exhibit 21
UNITED STATES STEEL CORPORATION
SUBSIDIARIES AND JOINT VENTURES AS OF DECEMBER 31, 2023
Company Name
Jurisdiction
Big River Steel International, Inc.
Delaware
Chisholm Coal LLC
Kentucky
Chrome Deposit Corporation
Indiana
Compagnie de Gestion de Mifergui- Nimba, LTEE
Delaware
Cygnus Mines Limited
Canada
Double G Coatings, Inc.
Delaware
Double G Coatings Company, L.P.
Delaware
Essex Minerals Company
New Jersey
Fairfield Primary Operations, LLC
Texas
GCW/USS Energy, LLC
Illinois
Grant Assurance Corporation
Vermont
Kanawha Coal LLC
West Virginia
Orinoco Mining Company
Delaware
Perdido Land Development Co., Inc.
Delaware
Pitcal Pipe, LLC
Delaware
Preserve Village Developers, LLC
Delaware
Stelco Holding Company
Delaware
Ontario Coal Company
Delaware
Ontario Eveleth Company
Minnesota
Ontario Hibbing Company
Minnesota
Hibbing Development Company
Minnesota
Hibbing Taconite Company
Minnesota
Stelco Coal Company
Pennsylvania
Stelco Erie Corporation
Delaware
Ontario Tilden Company
Michigan
Swan Point Yacht & Country Club, Inc.
Delaware
Timber Wolf Land, LLC
Delaware
海角涩区 China, LLC
Delaware
海角涩区 Holdco LLC
Delaware
Big River Steel Holdings LLC
Delaware
BRS Intermediate Holdings LLC
Delaware
Big River Steel LLC
Delaware
BRS Finance Corp
Delaware
Exploratory Ventures, LLC
Delaware
BRS Stock Holdco LLC
Delaware
Big River Steel Corp
Delaware
海角涩区 Blocker LLC
Delaware
海角涩区 Holdings, Inc.
Delaware
海角涩区 Global Holdings I B.V.
Netherlands
海角涩区 Global Holdings VI B.V.
Netherlands
海角涩区 Košice, s.r.o. (USSK)
Slovakia
Tubular s.r.oSlovakia
海角涩区 Europe - France S.A.
France
U.S. Steel Košice - SBS, s.r.o.
Slovakia
海角涩区 Europe - Germany GmbH
Germany
海角涩区 Global Holdings II, B.V.
Netherlands
海角涩区 Canada Limited Partnership
Canada
海角涩区 LRD Canada North Inc.
Canada
海角涩区 Mining Company, LLC
Alabama



UNITED STATES STEEL CORPORATION
SUBSIDIARIES AND JOINT VENTURES AS OF DECEMBER 31, 2023

海角涩区 Timber Company, LLC
Alabama
海角涩区 Tubular Products, LLCDelaware
Lone Star Steel Holdings, Inc.
Delaware
Lone Star Steel Holdings II, Inc.
Oklahoma
海角涩区 Tubular Products Middle East DMCC
Dubai, UAE
海角涩区 Oilwell Services, LLC
Delaware
Patriot Premium Threading Services, LLC
Delaware
USS Construction Products, LLC
Delaware
海角涩区 Tubular Products Canada ULC
Canada
Zinklahoma, Inc.
Delaware
海角涩区 Tubular Products Holdings, LLC
Texas
海角涩区 Seamless Tubular Operations, LLC
Texas
Star Brazil US, LLC 2
Texas
Star Brazil US, LLC 1Texas
Lone Star Brazil Holdings 1 Ltda.Brazil
UEC Technologies, LLC
Pennsylvania
USX Engineers and Consultants
Delaware
UEC Sail Information Technology, LTD.
India
United States Steel International, Inc.
New Jersey
United States Steel Export Company de Mexico, S.R.L. de C.V.
Mexico
United States Steel International de Mexico, S.R.L. de C. V.
Mexico
USS Galvanizing, Inc.
Delaware
PRO-TEC Coating Company, LLC
Delaware
PRO-TEC Coating Company, Inc.
Ohio
USS International Services, LLC
Delaware
USS Lakeside, LLC
Delaware
Chicago Lakeside Development, LLC
Delaware
CLD Parcel 14 LLCDelaware
CLD Adjoining Residential Parcels LLCDelaware
USS Oilwell Supply Co., LTD.
Delaware
USS Oilwell Tubular, Inc.
Delaware
USS Portfolio Delaware, Inc.
Delaware
USS Ventures, LLC
Delaware
USS WSP, LLC
Delaware
Worthington Specialty Processing
Michigan
ProCoil Company, LLC
Delaware
USS-UPI, LLC
Delaware
USX International Sales Company, Inc.
Barbados
Ventures RE Company I, LLCDelaware
Ventures RE Company II, LLCDelaware
Warrior & Gulf Navigation LLCAlabama