Explore DC’s last great swamp, Dyke Marsh Habitat

Best time to go: 09/01 - 10/31  

 Directions to Dyke Marsh Trail

WAS DC BUILT on a swamp? Naturalists and historians seem to disagree on this point. When L’Enfant laid out the plan for Washington, DC, he complained that the land was “swampy” and so began the myth of Washington as a giant swamp in need of draining. [1] But DeToqueville would later write to his father that Washington was built on “an arid plain scorched by the sun.” [2]

The trailhead to the Dyke Marsh Wildlife Habitat is just off the GW Parkway south of Alexandria, VA
The trailhead to the Dyke Marsh Wildlife Habitat is just off the GW Parkway south of Alexandria, VA

Dyke Marsh Wildlife Habitat

So which is it? Swamp or arid plain? You can find the answer for yourself by touring one of the last pieces of the original landscape that predated the city. Just south of Old Town Alexandria is the Dyke Marsh Wildlife Habitat, nearly 500 acres of sodden land along the Potomac shore, among DC’s Best Hikes for Kids.

We saw this beautiful Hibiscus blooming along the Potomac wetlands south of Alexandria in the Dyke Marsh Preserve
We saw this beautiful Hibiscus blooming along the Potomac wetlands south of Alexandria in the Dyke Marsh Preserve

Begin in the lot just off the GW Parkway that leads to the small boat marina. From the marina, you can rent sailboats, canoes and paddleboards, which will allow you to explore parts of the marsh not accessible by foot.

At the end of the 3/4 mile path from the parking lot is a short boardwalk going out into the marshland at Dyke Marsh Wildlife Preserve.
At the end of the 3/4 mile path from the parking lot is a short boardwalk going out into the marshland at Dyke Marsh Wildlife Preserve.

There is also an excellent 3/4 mile trail that leads out to a small promontory with sweeping views of the marsh and river. Along the way, you’ll find many examples of swamp fauna, as well as migratory birds who rest on the islands on their way to their vacation homes in Florida.

The trail out to the Dyke Marsh Wildlife Preserve is 3/4 mile each way.
The trail out to the Dyke Marsh Wildlife Preserve is 3/4 mile each way.

The trail also affords broad views of National Harbor, just across the river from the preserve. Paddleboards and sailboats race in the gentle currant of the Potomac as it opens out to the Chesapeake Bay.

Paddleboarders and Sailboats enjoy a sunny day along the Potomac River
You can rent a Paddleboard or a sailboat at the boat landing next to Dyke Marsh Preserve on the Potomac River south of Old Town Alexandria

When Jefferson drew an initial sketch of the city for L’Enfant’s study, he noted a swampy lowland river in front of the White House, which he fancifully named the Tiber. Where is the Tiber today? It still flows deep beneath the bustling traffic of Constitution Avenue.

The swamp (or marsh, if you prefer) is declining fast. Conservationists expect it to be completely gone by 2035, when it succumbs to the build-up of silt from the many construction projects of our growing city. Without a major conservation investment, it will likely share the fate of the mighty Tiber.

Explore More

  1. Widmer, Ted. “Draining the Swamp.” The New Yorker, The New Yorker, 19 Jan. 2017. Accessed 5 Aug. 2020.
  2. De Tocqueville, Alexis Letters From America, edited and translated by Frederick Brown. New Haven, CN: Yale University Press. 2010.

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More information: nps.gov