Ancient Trees in Washington DC
ancienttrees.app

The Grant Memorial Bur Oak
Bur Oak (Quercus macrocarpa). roughly 175 years, possibly older. Free, fully public. Stands on open U.S. Capitol Grounds parkland (Union Square), no restriction, viewable and approachable year-round.

The First Cherry Trees of the Tidal Basin
Yoshino Cherry (Prunus x yedoensis). roughly 114 years. Free, fully public. Stand on open NPS parkland along the Tidal Basin path, walkable any time.

The Battery Kemble Chestnut Oak
Chestnut Oak (Quercus montana). over 165 years, likely pre-dating the Civil War. Free, fully public NPS park (part of the Civil War Defenses of Washington / Rock Creek Park system), open trails and lawn, no restriction on viewing.

The National Mall Jefferson Elm
American Elm (Ulmus americana 'Jefferson'). roughly 91 years. Free, fully public. Stands in the open lawn of the National Mall, one of the most visited public spaces in the US, no restriction.

The Washington Monument Witness Mulberry
White Mulberry (Morus alba). roughly 130-140 years. Free, fully public. Stands on open NPS parkland on the Washington Monument grounds, directly on a paved circular path, unrestricted viewing.

The Botanic Garden Elm
Caucasian Elm (Zelkova carpinifolia). roughly 175 years, possibly older. Free, fully public. Stands on open U.S. Capitol Grounds parkland (Union Square), unrestricted viewing, about 350m from the Grant Memorial Bur Oak (wdc_001) in the same square.

The Arboretum Willow Oak
Willow Oak (Quercus phellos). rumoured to date to the Civil War era, confirmed fully grown by the 1940s. Free. U.S. National Arboretum, open to the public daily (check usna.usda.gov for current hours), no admission fee.

The Survey Lodge Catalpas
Catalpa (Catalpa sp.). roughly 124 years. Free, fully public. Stand in the open on NPS parkland right by the Survey Lodge Ranger Station building (itself closed to the public, used as an NPS office), on the walking paths southwest of the Washington Monument.

The Willow Oak Circle
Willow Oak (Quercus phellos). at least 45 years, possibly around a century. Free, fully public. Stands in the open on NPS parkland (Constitution Gardens / West Potomac Park) just south of the Vietnam Women's Memorial, no restriction.

The Cork Trees of the FDR Memorial
Amur Cork Tree (Phellodendron amurense). at least 80 years as of the original 2006 HALS survey, so roughly 100 years now. Free, fully public. Stand in the open on NPS parkland within the FDR Memorial (no admission fee, open 24 hours, staffed during the day), directly on the waterfront path.