United States National Arboretum

The United States National Arboretum is a 446-acre public botanical research and display garden in northeast Washington, D.C., established by Congress in 1927. It houses national collections of trees, shrubs and ornamental plants and serves research, conservation and public education roles.

Key attractions include formal gardens, large specimen collections of azaleas and maples, and specialty displays such as the National Bonsai & Penjing Museum and the relocated Capitol Columns. The grounds contain extensive planted collections spread across rolling terraces and meadows, suitable for walking and photography.

The arboretum was created by federal legislation and developed through planting programs and landscape design over the 20th century to support horticultural research and public outreach. Management is by the U.S. Department of Agriculture’s Agricultural Research Service in partnership with the National Arboretum Foundation.

Located in the northeastern quadrant of Washington, D.C., the arboretum sits east of the U.S. Capitol and north of the Anacostia River. It is accessible by road and public transit from central Washington.

• Admission and hours: Admission to the arboretum is free and the grounds are open year-round, though individual features may have seasonal hours.
• Best time to visit: Spring and early summer are peak times for the azalea and flowering collections; late summer to fall highlights include the tree collections and formal gardens.

What to See #

• National Bonsai & Penjing Museum: A living collection of miniature trees and classical penjing displays, housed in indoor and outdoor exhibits with specimens up to several decades old.
• National Grove of State Trees: A planted area featuring 50 plus state trees and groves representing each U.S. state and territory, established to showcase native tree species.
• Capitol Columns: A set of 22 freestanding Corinthian columns from the U.S. Capitol, relocated and displayed on a grassy terrace as a prominent landmark on the grounds.