Washington, D.C. and Bethesda, Md.
Length: 21 miles
Description: It’s a tried-and-true D.C. standard, and that’s because it’s a good length, it has a lot of variety and there aren’t many interruptions. There are no dramatic hills, water fountains throughout and you’re probably going to see a lot of other runners doing the same loop.
Cons: None, really.
Pros: You cross one major road—East-West Highway in Kensington. Much of Beach Drive in Rock Creek Park is closed to traffic on weekends and federal holidays until about 7 p.m. before a workday.
Tricky Points: Some portions of Beach Drive in Rock Creek Park are open to traffic, but there aren’t many. The Rock Creek Trail south of Porter Street is a little tight. South of P Street, it’s pretty exposed to the sun for about a mile. I guess it’s hard to get from the Georgetown Branch Trail to the Rock Creek Trail, but there are signs. There can be big swarms of cyclists on Beach Drive sometimes.