Straddling the Fauquier/Prince William County line, the Preserve occupies 2,486 acres of rocky ridges and steep valleys. The varied topography and geology of the site yield several forest and woodland community types with excellent wildlife viewing.
The Bull Run Mountains Conservancy (BRMC) maintains several hiking trails and offers interpretive and environmental education programs based on research conducted at the preserve.
Located near the preserve's Mountain House and parking area, Chapman's/Beverley Mill adds a dimension of human history to a site already rich in natural history. The 'Turn the Mill Around Campaign' is focused on restoring Chapman's/Beverley Mill and developing interpretive programming at the site.