EXHIBIT 21.1 SUBSIDIARIES OF ST. MARY LAND & EXPLORATION COMPANY A. Wholly-owned subsidiaries of St. Mary Land & Exploration Company, a Delaware corporation: 1. St. Mary Minerals, Inc., a Colorado corporation 2. Parish Corporation, a Colorado corporation 3. St. Mary Operating Company, a Colorado corporation 4. Nance Petroleum Corporation, a Montana corporation 5. St. Mary Energy Company, a Delaware corporation 6. Roswell LLC, a Texas limited liability company 7. Four Winds Marketing LLC, a Colorado limited liability company 8. GNK Acquisition Corp., a Texas corporation B. Other subsidiaries of St. Mary Land & Exploration Company 1. Box Church Gas Gathering LLC, a Colorado limited liability company (58.6754%) 2. Centennial Oil & Gas LLC, a Texas limited liability company (50%) 3. Trinity River Services LLC, a Texas limited liability company (25%) C. Wholly-owned subsidiaries of Nance Petroleum Corporation 1. NPC Inc., a Colorado corporation D. Wholly-owned subsidiaries of Parish Corporation: 1. Natasha Corporation, a Colorado corporation 2. Lucy Corporation, a Colorado corporation E. Partnership interests held by Parish Corporation: 1. Hilltop Investment Partners, a Colorado general partnership (50%) 2. C-470 Venture, a Colorado general partnership (68.858%) 3. ParishVentures, a Colorado general partnership (100%) F. Subsidiaries of Lucy Corporation: 1. St. Mary East Texas LP, a Texas limited partnership (99%) (the remaining 1% interest is held by St. Mary Land & Exploration Company)