Potomac Heritage–C&O Canal Loop
From Roosevelt Island follow the Potomac Heritage Trail 4 miles to Chain Bridge. Cross the Potomac River on Chain Bridge and pick up the C&O Canal Towpath and follow for 3.25 miles into Georgetown. After crossing under Key Bridge, leave the towpath on the small footbridge and climb up to Key Bridge through Francis Scott Key Park. Run across Key Bridge back to your car at Roosevelt Island.
To extend this run you can pick up the Battery Kimble Trail when you get to Fletcher's Cove. See the Glover-Archbold–Palisades–C&O Canal Loop.
Note that the Potomac Heritage Trail is prone to flooding south of Chain Bridge, so this run is not advisable in the spring or after a hard rain.
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