A casually updated, personally verified list of natural swimming and wading spots near Washington, DC. Note: Near is a nearly impossible to pin down word when used to describe distances, but for the purposes of this list I am counting anything that might reasonably hit up on weekend away. Map points denote parking location. I find the map the easiest way to navigate but I'll also group by State, then by driving distance from Union Station in, DC. These are generally places where you'll be swimming at your own risk, without a lifeguard, so always known your own abilities and never get in if the current looks too strong. Many thanks to SwimmingHoles.org, HikingUpward, and the various strangers who have pointed me to fresh spots.
Henryton, MD
In town
But first, consider: Do you even need to leave the city? The District has an expansive series of seasonal outdoor pools plus indoor pools open year-round and available for free to residents. There are also fountains, such as the elusive Meridian Hill Park cascades, and splash parks. And the more adventurous can explore these almost wilderness options:
Maryland
Within 60 minutes of DC
Virginia
Within 120 minutes of DC