The United States National Arboretum is an arboretum in northeast Washington, D.C., operated by the United States Department of Agriculture's Agricultural Research Service. It was established in 1927 by an act of Congress after a campaign by USDA Chief Botanist Frederick Vernon Coville. It is in size and is located northeast of the Capitol building, with entrances on New York Avenue, NE and R Street, NE. The campus's gardens, collections, and features are connected by roadways that are long in total. In addition to the main campus in Washington, D.C., there are research locations at the Henry A. Wallace Beltsville Agricultural Research Center in Beltsville, Maryland and in McMinville, Tennessee. The Arboretum functions as a major center of botanical research conducted by the USDA, including applied research on trees, shrubs, turf, and the development of new ornamental plants. In addition to a library and a historical collection (archive), the institution also has an extensive herbarium of over 800,000 specimens documenting wild and cultivated plant diversity. History The United States National Arboretum was formally established by an act of Congress on 4 March 1927. The act authorized the creation of the arboretum on what was then called Mount Hamilton, but it did not actually appropriate any funding to make that happen. That particular area was well-suited for the arboretum because it had varied soils and physiography, and no permanent buildings were then present. Ten months later, President Calvin Coolidge signed a law appropriating $300,000 for the National Arboretum. An initial were purchased in 1928, with an additional being acquired in 1934. Additional land was purchased in 1938, 1948, and 1949 that, along with subsequent minor expansions, contributed to the Arboretum's current footprint of . On April 11, 1973, the U.S. National Arboretum was listed as a Category II Landmark in the National Register of Historic Places for its "importance which contributes significantly to the cultural heritage and visual beauty of the District of Columbia." The construction of a Chinese garden, the National China Garden has been proposed for the National Arboretum since 2003. A groundbreaking was held in 2016 but the garden was reportedly cancelled due to counter-intelligence concerns regarding the construction of a large pagoda that could be used for collecting signals intelligence. Gardens and collections Major gardens Asian Collections Japanese Woodland, Asian Valley, China Valley, and Korean Hillside Fern Valley Native Plant Collections Woodland, prairie, and Southeastern Coastal Plain