Sentier du lac Cash

Established in 1936 by executive order of President Franklin D. Roosevelt, the Patuxent Research Refuge is the only National Wildlife Refuge in the United States 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.