The Corps of Engineers and the US Forest Service have joined together to create a national system for reserving recreation facilities. The National Recreation Reservation Service (NRRS TM) is available to take reservations.
This system allows you to check campsite availability and reserve a campsite at Corps or Forest Service sites throughout the United States. You can use the system by calling a toll free number (877-444-6777), accessing the internet site http://www.recreation.gov/.
Campsites may be reserved up to 240 days in advance, and group facilities such as picnic shelters may be reserved up to 360 days in advance. Of course, campsites will still be available on-site without a reservation.
More information on national recreation opportunities is available at: (note that these are off this server)