The Patuxent Research Refuge is a National Wildlife Refuge in Prince George's County, Maryland, United States, established in 1936 by executive order of President Franklin D. Roosevelt. It is the only National Wildlife Refuge in the country established to support wildlife research. With land surrounding the Patuxent and Little Patuxent Rivers between Washington, D.C. and Baltimore, Maryland, the refuge has grown from the original 2,670 acres (10.8 km2) to its present size of over 12,800 acres (52 km2) and encompasses land formerly managed by the Departments of Agriculture and Defense. Throughout decades of change, Patuxent's mission of conserving and protecting the nation's wildlife and habitat through research and wildlife management techniques has remained virtually unchanged.