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Exhibit 21
ONEOK, Inc.

SUBSIDIARIES OF THE COMPANY
AS OF DECEMBER 31, 2025
Subsidiaries
State of
Incorporation
or Organization
Acacia Natural Gas, L.L.C.Delaware
Ascension Pipeline Company, LLC (50%)Delaware
Bighorn Gas Gathering, L.L.C. (49.0%)Delaware
Bison Prairie Assurance, L.L.C.Oklahoma
Black Mesa Holdings, Inc.Delaware
Black Mesa Pipeline, Inc.Delaware
Black Mesa Pipeline Operations, L.L.C.Delaware
Black Mesa Technologies, Inc.Oklahoma
Border Midwestern CompanyDelaware
Bridgeline Holdings, L.P.Delaware
BridgeTex Pipeline Company, LLC (60%)Delaware
Cedar Cove Midstream LLC (30%)Delaware
Chisholm Pipeline Company (50%)Delaware
Chisholm Pipeline Holdings, L.L.C.Delaware
Cowtown Gas Processing Partners, L.P.Texas
Cowtown Pipeline Partners L.P.Texas
Crestone Energy Ventures, L.L.C.Delaware
Crestone Gathering Services, L.L.C.Delaware
Crestone Powder River, L.L.C.Delaware
Crestone Wind River, L.L.C.Delaware
Double Eagle Pipeline LLC (50%)
Delaware
Eiger Express Holdings, LLC (25.5%)Delaware
Elk Merger Sub II, L.L.C.Delaware
EnLink Barnett Gas Services GP, LLCDelaware
EnLink Barnett Gas Services, LLCDelaware
EnLink Calcasieu, LLCDelaware
EnLink CCS, LLCDelaware
EnLink Crude Marketing, LLCDelaware
EnLink Crude Pipeline LLC Texas
EnLink Delaware Crude Pipeline, LLCTexas
EnLink Energy GP, LLCDelaware
EnLink Gas Marketing, LPTexas
EnLink LIG Liquids, LLCLouisiana
EnLink LIG, LLCLouisiana
EnLink Louisiana Gathering, LLCLouisiana
EnLink Matli Holdings, LLCDelaware
EnLink Midcon Transport, LLCDelaware
EnLink Midcon, LLCDelaware
EnLink Midstream Finance CorporationDelaware
EnLink Midstream Funding, LLCDelaware
EnLink Midstream GP, LLCDelaware
EnLink Midstream Holdings GP, LLCDelaware
1


EnLink Midstream Holdings, LPDelaware
EnLink Midstream Operating GP, LLCDelaware
EnLink Midstream Operating, LPDelaware
EnLink Midstream Manager, LLC
Delaware
EnLink Midstream Partners, LPDelaware
EnLink Midstream Services, LLC
Texas
EnLink MXP Holding, LLCDelaware
EnLink NGL Marketing, LPTexas
EnLink NGL Pipeline, LPTexas
EnLink Nominee, LLCDelaware
EnLink North Texas Gathering, LPTexas
EnLink Oklahoma Crude Gathering, LLCDelaware
EnLink Oklahoma Gas Processing, LP
Delaware
EnLink Pelican, LLCDelaware
EnLink Permian II, LLCTexas
EnLink Permian, LLCTexas
EnLink Processing Services, LLCDelaware
EnLink SE Texas Crude Pipeline, LLCDelaware
EnLink Texas NGL Pipeline, LLCTexas
EnLink Texas Processing, LPTexas
EnLink Tuscaloosa, LLCLouisiana
Fort Union Gas Gathering, L.L.C. (50%)Delaware
GIP III Trophy GP, LLCDelaware
Gulf Coast Fractionators (38.75%)Texas
Heartland Pipeline Company (general partnership) (50%)Texas
HoustonLink Pipeline Company, LLC (50%)Delaware
Jefferson Island Storage & Hub, L.L.C.Delaware
Lost Creek Gathering Company, L.L.C. (35%)Delaware
Louisiana River Market, LLCDelaware
Magellan Ammonia Pipeline, L.P.Delaware
Magellan Asset Services GP, LLC
Delaware
Magellan Asset Services, L.P.Delaware
Magellan Crude Oil Pipeline Company GP, LLCDelaware
Magellan Crude Oil Pipeline Company, L.P.Delaware
Magellan GP, LLCDelaware
Magellan Logistics & Services GP, LLC
Delaware
Magellan Logistics & Services, L.P.Delaware
Magellan Midstream Holdings GP, LLCDelaware
Magellan Midstream Partners, L.P.Delaware
Magellan NGL, LLC
Delaware
Magellan OLP, L.P. Delaware
Magellan Operating Company, LLC
Delaware
Magellan Operating GP, LLC Delaware
Magellan Pipeline Company, L.P. Delaware
Magellan Pipeline GP, LLC Delaware
Magellan Pipeline Terminals GP, LLCDelaware
Magellan Pipeline Terminals, L.P. Delaware
Magellan Pipelines Holdings GP, LLC
Delaware
Magellan Pipelines Holdings, L.P.Delaware
2


Magellan Processing GP, LLCDelaware
Magellan Processing, L.P. Delaware
Magellan Terminals Holdings, L.P.Delaware
MBTC Pipeline LLC (80%)
Delaware
MDP Holdings, LLCDelaware
Medallion Crude Oil Logistics, LLCTexas
Medallion Gathering & Processing, LLCTexas
Medallion Midland Acquisition, L.P.Delaware
Medallion Midland Acquisition Partnership, L.P.Delaware
Medallion Midland Gathering, LLCTexas
Medallion Midland Partners, LLCDelaware
Medallion Operating Company, LLCDelaware
Medallion Parent Holdings, L.L.C.Delaware
Medallion Pipeline Company, LLCTexas
Medallion Producer Services, LLCTexas
MGP Marketing, LLCTexas
MidCon Express, LLC (f/k/a Lazarus Gas Gathering, LLC)
Texas
Mid Continent Market Center, L.L.C.Kansas
Mont Belvieu I Fractionation Facility (joint venture) (80%)Texas
MVP Terminalling, LLC (25.01%)Delaware
MXP Parent, LLC (15%)Delaware
Nine MileCo, LLCTexas
Northern Border Pipeline Company (general partnership) (50%)Texas
OkTex Pipeline Company, L.L.C.Delaware
ONEOK Arbuckle II Pipeline, L.L.C.Oklahoma
ONEOK Arbuckle North Pipeline, L.L.C.Delaware
ONEOK Arbuckle Pipeline, L.L.C.Delaware
ONEOK Bakken Pipeline, L.L.C.Delaware
ONEOK Bushton Processing, L.L.C.Delaware
ONEOK Crude Marketing, L.L.C.
Delaware
ONEOK Delaware Gathering, LLC (f/k/a Delaware G&P LLC)
Delaware
ONEOK Delaware Midstream, LLC (f/k/a Delaware Processing LLC)
Delaware
ONEOK Elk Creek Pipeline, L.L.C.Oklahoma
ONEOK Energy Services Company, IIDelaware
ONEOK Energy Services Company, L.P.Texas
ONEOK Energy Services Holdings, L.L.C.Oklahoma
ONEOK Field Services Company, L.L.C.Oklahoma
ONEOK Gas Storage Holdings, L.L.C.Delaware
ONEOK Gas Storage, L.L.C.Oklahoma
ONEOK Gas Transportation, L.L.C.Oklahoma
ONEOK Gulf Coast Pipeline, L.L.C.Delaware
ONEOK Hydrocarbon GP, L.L.C.Delaware
ONEOK Hydrocarbon Holdings, L.L.C.Delaware
ONEOK Hydrocarbon Southwest, L.L.C.Delaware
ONEOK Hydrocarbon, L.L.C.Delaware
ONEOK Hydrocarbon, L.P.Delaware
ONEOK ILP GP, L.L.C.Delaware
ONEOK Leasing CompanyDelaware
ONEOK MB I, L.P.Delaware
3


ONEOK Midland Midstream, LLC (f/k/a Coronado Midstream LLC)
Texas
ONEOK Midstream Gas Supply, L.L.C.Oklahoma
ONEOK Mont Belvieu Properties, L.L.C.Delaware
ONEOK Mont Belvieu Storage Company, L.L.C.Delaware
ONEOK NGL Distribution System, L.L.C.Texas
ONEOK NGL Gathering, L.L.C.Delaware
ONEOK NGL Pipeline, L.L.C.Delaware
ONEOK North System, L.L.C.Delaware
ONEOK Northern Border Pipeline Company Holdings, L.L.C.Oklahoma
ONEOK Overland Pass Holdings, L.L.C.Oklahoma
ONEOK Parking Company, L.L.C.Delaware
ONEOK Partners GP, L.L.C.Delaware
ONEOK Partners Intermediate Limited PartnershipDelaware
ONEOK Partners, L.P.Delaware
ONEOK Permian NGL Operating Company, L.L.C.Delaware
ONEOK Pipeline Holdings, L.L.C.Delaware
ONEOK Power Solutions, L.L.C.
Delaware
ONEOK Rockies Investments, L.L.C.Delaware
ONEOK Rockies Midstream, L.L.C.Delaware
ONEOK Services Company, L.L.C.Oklahoma
ONEOK Southeast Texas NGL Pipeline, L.L.C.Oklahoma
ONEOK Sterling III Pipeline, L.L.C. Oklahoma
ONEOK TCX Holdings, L.L.C.Delaware
ONEOK Texas Gas Storage, L.L.C.Texas
ONEOK Underground Storage Company, L.L.C.Kansas
ONEOK Unit Holdings, Inc.Delaware
ONEOK Ventures, L.L.C.Oklahoma
ONEOK Ventures Direct Investments, L.L.C.Oklahoma
ONEOK Ventures Fund Investments, L.L.C.Oklahoma
ONEOK VESCO Holdings, L.L.C.Delaware
ONEOK West Texas NGL Pipeline, L.L.C.Texas
ONEOK Western Trail Pipeline, L.L.C.Oklahoma
ONEOK WesTex Transmission, L.L.C.Delaware
ONEOK Wyoming Midstream, L.L.C.
Delaware
ONEOK Wyoming Midstream Holdings, L.L.C.
Delaware
Overland Pass Pipeline Company LLC (50%)Delaware
Powder Springs Logistics, LLC (50%)Delaware
Redcliff Midstream, LLCDelaware
Roadrunner Gas Transmission Holdings, LLC (50%)Delaware
Roadrunner Gas Transmission, LLC (100% owned by Roadrunner Gas Transmission Holdings, LLC)Delaware
Sabine Hub Services LLCDelaware
Sabine Pass Plant Facility Joint VentureTexas
Sabine Pipe Line LLCDelaware
Saddlehorn Pipeline Company, LLC (40%)Delaware
Saguaro Connector Pipeline, L.L.C.Delaware
Saguaro Connector Pipeline Holdings, L.L.C.Delaware
Seabrook Logistics, LLC (50%)Delaware
Seabrook Pipeline, LLC (100% owned by Seabrook Logistics, LLC)
Delaware
4


Seabrook Terminal, LLC (100% owned by Seabrook Logistics, LLC)
Delaware
Sun Belt Connector, L.L.C.
Delaware
SWG Pipeline, L.L.C.Texas
Texas City Logistics LLC (50%)
Delaware
Texas Frontera, LLC (50%)Delaware
Tiburon Operating LLCTexas
TOM-STACK, LLCDelaware
TXGC Pipelines, L.L.C.Delaware
TXGC Properties, L.L.C.Delaware
Venice Energy Services Company, L.L.C. (10.1765%)Delaware

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