- Prince William Forest Park Located near Washington D.C in Triangle, VA TRAVEL BASICS - CAMPING - LODGING ACTIVITIES - FACILITIES - FEES/PERMITS Welcome to Prince William Forest Park. (Reine Wonite) IN BRIEF Located in Prince William County, Virginia, Prince William Forest Park is the largest natural area in the Washington, DC, metropolitan region at over 17, 000 acres. It was created in August ...www.nps.gov/prwi