Exhibit 21
| ENTITY | JURISDICTION | |
| ACMP Finance Corp. | Delaware | |
| Access Compression, L.L.C. | Oklahoma | |
| Access MLP Operating, L.L.C. | Delaware | |
| Access Midstream Gas Services, L.L.C. | Oklahoma | |
| Access Midstream Ventures, L.L.C. | Delaware | |
| Access Permian Midstream, L.L.C. | Oklahoma | |
| Access West Texas Processing, L.L.C. | Oklahoma | |
| Alliance Canada Marketing L.P. | Alberta | |
| Alliance Canada Marketing LTD | Alberta | |
| Appalachia Midstream Services, L.L.C. | Oklahoma | |
| Aux Sable Liquid Products Inc. | Delaware | |
| Aux Sable Liquid Products LP | Delaware | |
| Aux Sable Midstream LLC | Delaware | |
| Bargath LLC | Delaware | |
| Baton Rouge Fractionators LLC | Delaware | |
| Baton Rouge Pipeline LLC | Delaware | |
| Black Marlin Pipeline LLC | Texas | |
| Blue Racer Midstream LLC | Delaware | |
| Bluestem Gas Services, L.L.C. | Oklahoma | |
| Caiman Energy II, LLC | Delaware | |
| Caiman Ohio Midstream, LLC | Texas | |
| Carbon County UCG, Inc. | Delaware | |
| Carbonate Trend Pipeline LLC | Delaware | |
| Cardinal Gas Services, L.L.C. | Delaware | |
| Cardinal Operating Company, LLC | Delaware | |
| Cardinal Pipeline Company, LLC | North Carolina | |
| Constitution Pipeline Company LLC | Delaware | |
| Discovery Gas Transmission LLC | Delaware | |
| Discovery Producer Services LLC | Delaware | |
| DMP New York, Inc. | New York | |
| Gulf Liquids New River Project LLC | Delaware | |
| Gulfstar One LLC | Delaware | |
| Gulfstream Management & Operating Services, L.L.C. | Delaware | |
| Gulfstream Natural Gas System, L.L.C. | Delaware | |
| HB Construction Company Ltd. | Alberta | |
| HI-BOL Pipeline LLC | Delaware | |
| Inland Ports, Inc. | Tennessee | |
| Jackalope Gas Gathering Services, L.L.C. | Oklahoma | |
| Laurel Mountain Midstream Operating LLC | Delaware | |
| Laurel Mountain Midstream, LLC | Delaware | |
| LNE Pipeline Corporation | New York | |
| Louisiana Midstream Gas Services, L.L.C. | Oklahoma | |
| Magnolia Midstream Gas Services, L.L.C. | Oklahoma | |
| Marsh Resources, LLC | Delaware | |
| ENTITY | JURISDICTION | |
| Mid-Continent Fractionation and Storage, LLC | Delaware | |
| Mockingbird Midstream Gas Services, L.L.C. | Oklahoma | |
| Northwest Pipeline LLC | Delaware | |
| Oklahoma Midstream Gas Services, L.L.C. | Oklahoma | |
| Overland Pass Pipeline Company LLC | Delaware | |
| Pacific Connector Gas Pipeline, LLC | Delaware | |
| Pacific Connector Gas Pipeline, LP | Delaware | |
| Parachute Pipeline LLC | Delaware | |
| Parkco Two, L.L.C. | Oklahoma | |
| Pecan Hill Water Solutions | Delaware | |
| Pine Needle LNG Company, LLC | North Carolina | |
| Pine Needle Operating Company, LLC | Delaware | |
| Ponder Midstream Gas Services, L.L.C. | Delaware | |
| Ranch Westex JV LLC | Delaware | |
| Reserveco Inc. | Delaware | |
| TWC Holdings C.V. | Netherlands | |
| Texas Midstream Gas Services, L.L.C. | Oklahoma | |
| The Williams Companies Foundation, Inc. | Oklahoma | |
| The Williams Companies, International Holdings B.V. | Dutch BV | |
| Three Rivers Midstream LLC | Delaware | |
| TransCardinal Company, LLC | Delaware | |
| TransCarolina LNG Company, LLC | Delaware | |
| Transco Energy Company, LLC | Delaware | |
| Transco Exploration Company | Delaware | |
| Transcontinental Gas Pipe Line Company, LLC | Delaware | |
| Utica East Ohio Midstream, L.L.C. | Delaware | |
| Utica Gas Services, L.L.C. | Oklahoma | |
| VHMS LLC | Delaware | |
| Wamsutter LLC | Delaware | |
| WFS Liquids LLC | Delaware | |
| WFS - Pipeline LLC | Delaware | |
| WFS Enterprises, LLC | Delaware | |
| WFS Gathering Company, L.L.C. | Delaware | |
| WilPro Energy Services (El Furrial) Limited | Cayman Islands | |
| WilPro Energy Services (Pigap II) Limited | Cayman Islands | |
| Williams Acquisition Holding Company LLC | New Jersey | |
| Williams Alaska Petroleum, Inc. | Alaska | |
| Williams Bayou Ethane Pipeline, LLC | Delaware | |
| Williams Blu Operating LLC | Delaware | |
| Williams Bluegrass Pipeline LLC | Delaware | |
| Williams CV Holdings LLC | Delaware | |
| Williams Canada Employee Services Inc. | Alberta | |
| Williams Canada Propylene ULC | Alberta | |
| Williams Energy Canada Development ULC | Alberta | |
| Williams Energy Canada ULC | Alberta | |
| Williams Energy Resources LLC | Delaware | |
| Williams Energy Solutions LLC | Delaware | |
| ENTITY | JURISDICTION | |
| Williams Equities, Inc. | Delaware | |
| Williams Exploration Company | Delaware | |
| Williams Express, Inc. (AK) | Alaska | |
| Williams Express LLC | Delaware | |
| Williams Field Services - Gulf Coast Company, L.P. | Delaware | |
| Williams Field Services Company, LLC | Delaware | |
| Williams Field Services Group, LLC | Delaware | |
| Williams Flexible Generation, LLC | Delaware | |
| Williams Four Corners LLC | Delaware | |
| Williams Gas Pipeline Company, LLC | Delaware | |
| Williams Gas Processing - Gulf Coast Company, L.P. | Delaware | |
| Williams Global Energy (Cayman) Limited | Cayman Islands | |
| Williams Global Holdings LLC | Delaware | |
| Williams Gulf Coast Gathering Company, LLC | Delaware | |
| Williams Headquarters Building Company | Delaware | |
| Williams Horizon Offgas ULC | Alberta | |
| Williams Hutch Rail Company, LLC | Delaware | |
| Williams Information Technology, Inc. | Delaware | |
| Williams International (Bermuda) Limited | Bermuda | |
| Williams International Company LLC | Delaware | |
| Williams International El Furrial Limited | Cayman Islands | |
| Williams International Investments (Cayman) Limited | Cayman Islands | |
| Williams International Pigap Limited | Cayman Islands | |
| Williams International Services Company | Nevada | |
| Williams International Telecommunications Investments (Cayman) Limited | Cayman Islands | |
| Williams International Venezuela Limited | Cayman Islands | |
| Williams Laurel Mountain, LLC | Delaware | |
| Williams Memphis Terminal, Inc. | Delaware | |
| Williams Mid-South Pipelines, LLC | Delaware | |
| Williams Mobile Bay Producer Services, L.L.C. | Delaware | |
| Williams New Soda, Inc. | Delaware | |
| Williams Ohio Valley Midstream LLC | Texas | |
| Williams Ohio Valley Pipeline LLC | Delaware | |
| Williams Oil Gathering, L.L.C. | Delaware | |
| Williams Olefins Development, LLC | Delaware | |
| Williams Olefins Feedstock Pipelines, L.L.C. | Delaware | |
| Williams Olefins, L.L.C. | Delaware | |
| Williams Pacific Connector Gas Operator, LLC | Delaware | |
| Williams Partners Cooperatief U.A. | Netherlands | |
| Williams Partners Finance Corporation | Delaware | |
| Williams Partners GP LLC | Delaware | |
| Williams Partners L.P. (recognizing renamed ACMP) | Delaware | |
| Williams Partners Operating LLC | Delaware | |
| Williams PERK, LLC | Delaware | |
| Williams Petroleum Pipeline Systems, Inc. | Delaware | |
| Williams Petroleum Services, LLC | Delaware | |
| Williams Purity Pipelines, LLC | Delaware | |
| ENTITY | JURISDICTION | |
| Williams Refining & Marketing, L.L.C. | Delaware | |
| Williams Resource Center, L.L.C. | Delaware | |
| Williams Soda Holdings, LLC | Delaware | |
| Williams Sodium Products Company | Delaware | |
| Williams Strategic Sourcing Company | Delaware | |
| Williams TravelCenters, Inc. | Delaware | |
| WPZ GP LLC | Delaware | |