The United States Department of Agriculture (USDA) has maintained herbarium collections since about 1868. Plant and seed material of crop or economically important species was of particular interest to the Department, and scientists began collecting and preserving these samples shortly after USDA’s establishment in 1862. Over the next century, these collections grew in size and scope and were relocated several times, finally coming to the U.S. National Arboretum permanently in 1964.

The U.S. National Arboretum Herbarium houses around 700,000 specimens, approximately 25% of which are from cultivated, rather than wild, plants. This emphasis on cultivated material makes the herbarium here unique; it is one of the largest such collections in the United States and the world.