EXHIBIT 21

LIST OF SUBSIDIARIES ⁽¹⁾ 

At December 31, 2015

Anadarko Algeria Company LLC ⁽²⁾ 

a Delaware limited liability company,

Anadarko Brazil Investment I LLC

a Delaware limited liability company,

Anadarko Colombia Company

a Cayman Islands corporation,

Anadarko Consolidated Holdings LLC ⁽²⁾ 

a Delaware limited liability company,

Anadarko Development Company

a Cayman Islands corporation,

Anadarko E&P Onshore LLC ⁽²⁾ 

a Delaware limited liability company,

Anadarko Energy Holding Limited

a Gibraltar limited liability company,

Anadarko Energy Services Company ⁽²⁾ 

a Delaware corporation,

Anadarko Exploracao e Producao de Petroleo e Gas Natural Ltda.

a Brazil limited liability company,

Anadarko Global Energy S.à r.l. ⁽²⁾ 

a Luxembourg limited liability company,

Anadarko Holding Company ⁽²⁾ 

a Utah corporation,

Anadarko International Development S.à r.l. ⁽²⁾ 

a Luxembourg limited liability company,

Anadarko Land Corp

a Nebraska corporation,

Anadarko Marcellus Midstream, L.L.C.

a Delaware limited liability company,

Anadarko Midkiff/Chaney Dell LLC

a Delaware limited liability company,

Anadarko Offshore Holding Company, LLC ⁽²⁾ 

a Delaware limited liability company,

Anadarko Petroleum Corporation ⁽²⁾ 

a Delaware corporation,

Anadarko Realty, LLC

a Texas limited liability company,

Anadarko Rockies LLC

a Delaware limited liability company,

Anadarko Uintah Midstream, LLC

a Delaware limited liability company,

Anadarko US Offshore LLC ⁽²⁾ 

a Delaware corporation,

Anadarko USH1 Corporation ⁽²⁾ 

a Delaware corporation,

Anadarko WCTP Company

a Cayman Islands corporation,

Anadarko West Texas LLC

a Delaware limited liability company,

APC Midstream Holdings, LLC

a Delaware limited liability company,

Bitter Creek Coal Company

a Utah corporation,

Chipeta Processing LLC

a Delaware limited liability company,

Delaware Basin JV Gathering LLC

a Delaware limited liability company,

Delaware Basin Midstream, LLC

a Delaware limited liability company,

Kerr-McGee Corporation ⁽²⁾ 

a Delaware corporation,

Kerr-McGee Energy Services Corporation

a Delaware corporation,

Kerr-McGee Gathering LLC ⁽²⁾ 

a Colorado limited liability company,

Kerr-McGee Oil and Gas Onshore LP ⁽²⁾ 

a Delaware limited partnership,

Kerr-McGee Shared Services Company LLC ⁽²⁾ 

a Delaware limited liability company,

Kerr-McGee Worldwide Corporation ⁽²⁾ 

a Delaware corporation,

KM BM-C Seven Ltd. ⁽²⁾ 

a Cayman Islands limited liability company,

Rock Springs Royalty Company LLC

a Utah limited liability company,

Springfield Pipeline LLC

a Texas limited liability company,

Upland Industries Corporation

a Nebraska corporation,

Venezuela US SRL

a Barbados limited liability company,

Western Gas Holdings, LLC ⁽²⁾ 

a Delaware limited liability company,

Western Gas Partners, LP

a Delaware limited partnership,

Western Gas Resources, Inc. ⁽²⁾ 

a Delaware corporation,

WGR Asset Holding Company LLC ⁽²⁾ 

a Delaware limited liability company,

WGR Operating, LP ⁽²⁾ 

a Delaware limited partnership,

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⁽¹⁾ The names of certain subsidiaries have been omitted since, considered in the aggregate as a single subsidiary, they would not constitute a significant subsidiary, as of the end of the year covered by this report, as defined under the Securities and Exchange Commission Regulation S-X 210.1-02(w).

⁽²⁾  Subsidiary meets the conditions of a significant subsidiary under the Securities and Exchange Commission Regulation S-X 210.1-02(w).