Cattail Regional Park is home to mature forests, open fields, and an upland bog. NOVA Parks plans to develop a trail network there.

Rare old-growth Eastern hemlock trees, some of them 250 years old, grow about a mile down the Bull-Run Occoquan Trail from the trailhead at Hemlock Overlook Regional Park.

The Winkler Preserve is 45 acres of mature forest tucked between high-rise buildings and I-395.