Difficult Run / Tamarack Park
Fairfax County Park Authority
Vienna, VA

This trail mostly follows Difficult Run through Wolftrap Stream Valley Park, Difficult Run Stream Valley Park, and Tamarack Park. Colvin Run Mill Park provides the northern boundary of this trail run, while the Washington & Old Dominion (W&OD) Trail provides the southern boundary, at about the 14.5-mile marker.

Approximate Distance: 2 to 3 miles
Surface: Dirt, gravel, and some asphalt trails
Highlight: Tamarack Park wooded, dirt trail running

Location of trailheads
Northern trailhead
Southern trailhead

To run this trail from Colvin Run Mill Park, start from Carpers Farm Way near the intersection of Carpers Farm Way and Leesburg Pike. If needed, first visit the restrooms at Colvin Run Mill across Leesburg Pike.

Follow the dirt trail east through meadow and woods, with Leesburg Pike to your left. After about ½ mile, turn right onto the gravel trail that skirts along Wolftrap Stream Valley Park. The gravel path leads to Browns Mill Road.

At Browns Mill Road the gravel path takes a sharp turn to the right following the road. DO NOT follow the path west along Browns Mill Road.

Instead, cross B<<Selection in Document>>rowns Mill Road and then cross the road bridge over Difficult Run. Pick up the asphalt path to your immediate right that leads behind a residential community to your left. Difficult Run Stream Valley Park lies to your right, essentially a large meadow to the east side of Difficult Run. Keep the meadow to your right and do not take any left turns into the residential community.

After a few hundred yards, take the gravel path where you see the Dulles Toll Road (route 267) crossing Difficult Run. Follow the dirt path under the Toll Road and into another meadow on the other side.

Follow the dirt trail a very short distance along Sun Valley Park and cross another stream.

Shortly after crossing the stream, cross

 Difficult Run on circular, cement blocks.

 The path turns to gravel again.

Follow the gravel path to the Hunter Mill Estates residential community to your right. As you get close to the homes, take the dirt path to your left. Fairfax Cross-County Trail (CCT) markers indicate the entrance to the dirt path.

NOTE: If you do not bear to the left, but continue on the gravel path instead, the trail continues through park property and then follows a path into the Hunter Mill Estates residential community. The path eventually ends at Brittenford Drive, near the intersection with Landon Hill Road, for about 1 mile of extra running (one-way).

After bearing left into the woods, the trail immediately leads you to a small stream crossing — no bridge, so plan to get your feet wet. This wooded, dirt path offers fine trail running through Tamarack Park for about 1 mile. Follow the CCT markers through this segment of the trail. The wooded trail ends at the intersection of Difficult Run and the Washington and Old Dominion (W&OD) Trail, near the 14.5-mile marker.

Start at the southern border of this trail segment by parking at the intersection of Hunter Station Road and Hunter Mill Road. Follow the bridle trail portion of the W&OD east until you see the sign for Tamarack Park. Turn left onto the dirt path, turn right to cross the small foot bridge, cross the open, grass field, and enter the woods at the northeast corner of the field.

Alternatively, continue past the Tamarack Park sign for another 100 yards to Difficult Run and enter the woods on the dirt path to the left, heading north.

This trailhead also provides the following options:<<Selection in Document>>

• W&OD Trail east towards Vienna, Falls Church, and, eventually, Arlington, VA
• W&OD Trail west towards Reston, Herndon, Ashburn, Leesburg, and, eventually, Purcellville, VA
• Fairfax Cross-County Trail (CCT) south towards Reston, Fairfax, Annandale, Springfield, and, eventually, Occoquan, VA