Great Falls Park is closed at dark. Overnight camping is prohibited and there are no lodging facilities within the park.
There are many options for lodging within the immediate area. A web search will provide a variety of choices. Nearby towns include Reston, Herndon, Tysons Corner, Falls Church, Arlington, Alexandria, Sterling, and Washington D.C.
Fairfax County Park Authority
Northern Virginia Regional Park Authority
Chesapeake and Ohio Canal NHP
Prince William Forest National Park
Shenandoah National Park
Catoctin Mountain National Park
Greenbelt National Park