Don't forget the bug spray during the summer.
As always, check the Rock Creek Park home page for park warnings before beginning the hike.
There is parking across the street from Peirce Mill adjacent to the picnic area. It can fill up on weekend mornings when the weather is good. There is also some street parking along Tilden on your way to Peirce Mill from the east.
If you are coming via train, simply walk down Connecticut Ave (south) until you hit Tilden. Make a left and follow to Peirce Mill. Be careful walking along Tilden. There is not a sidewalk the entire distance to Peirce Mill.
This is a challenging hike. It has quit a few hills and can be very rocky, especially on the Valley Trail between the Police Station and Blagden (see map). This stretch of trail can also be very slick when wet. Given the hike's length and difficulty, it is not a good hike for kids.
You will also need to cross the street several times. These crossings can be blind, and let's just say not everybody obeys the local speed limit, so be extra careful.
Be vigilant when walking, as the trail splits occasionally making it easy to get on the wrong trail.
The attached map and trail instructions will help you stay on track.
If ten miles is too much, check out this article outlining three shorter hikes, each about three miles.