Camping options near Washington DC

There are not any campgrounds located in Washington DC.  The closest one that I know of is Lake Fairfax Park in Reston.  When we lived in Virginia they did have camping but there had been talk of closing down the campground portion of the park.  It is a very nice park with a HUGE waterpark and a carousel. From there you can drive down to DC in about an hour or you can drive about 10 minutes to a commuter lot that will take you to the Metro, which is very clean and safe.  Beyond that campground I can't think of any others.    The land here is so super expensive that campgrounds just can't survive.  Also remember that although hotels are expensive here, all the attractions are free.  All the monuments and museums are completely free to enter.  The only thing you'd probably pay for is a Tourmobile tour which is a great idea for your first day in town.  There are lots of less expensive hotels in Gaithersburg which is close to the end of the Metro's Red line.  Many of them have free shuttles to the Metro station.  You might be better off doing a hotel for two or three days around the DC suburbs and then camping somewhere else for a few nights.

I don't know if you are still looking for a campground or not.  But I just learned of a new one.  My dd had Girl Scout Encampment last week in a new location because of some last minute changes.  We'd never been to Greenbelt National Forest before but they have a lovely, large campground.  It is very close to DC and right near a Metro station so there is easy access to downtown.  The campground had a bathroom with showers.  It isn't the best part of the DC area but it isn't bad either.  It is safe and very close to the University of Maryland.  There is a large hotel and a TGIFridays right across the street from the entrance to the campground but once you get into the park, you'd think you were completely  removed from everything.