The United States National Arboretum is an arboretum in Washington, D.C., operated by the United States Department of Agriculture's Agricultural Research Service as a division of the Henry A. Wallace Beltsville Agricultural Research Center. It was established in 1927 by an act of Congress after a campaign by USDA Chief Botanist Frederick Vernon Coville.
It is 446 acres (1.80 km2) in size and is located 2.2 miles (3.5 km) northeast of the Capitol building, with entrances on New York Avenue and R Street, Northeast. Nine miles of roadways wind through and connect the numerous gardens and collections on the campus.
The arboretum functions as a major center of botanical research. It conducts wide-ranging basic and developmental research on trees, shrubs, turf, and floral plants. It has a library with 10,000 volumes and approximately 90 publications concentrating in botanical literature.