0.0 -- Start (Colvin Run Mill)
0.1 -- Cross Leesburg Pike (Route 7) at Carper’s Farm Way
0.15 --right on dirt trail. trail is marked with 6" x 6" white posts with black horseshoes
1.8 -- cross Hunter Mill Road
2.? -- off trail: restrooms (in valley) 0.3 miles west of Hunter Mill Rd.
2.0 -- turn left, ascending gravel trail, cross athletic field;
2.4 -- descend steeply and ford small stream
3.5 -- cross field next to fence, follow red blazes on descending trail
4.1 -- ford small stream, turning sharply left.
5.5 -- becomes Michael Faraday Drive, rear parking lot of #1807 M. Faraday (end of posts with horseshoes.)
5.7 -- left gravel trail next to bike trail
5.? -- right on bike trail to fast-food eateries and restrooms at Wiehle Ave. 1 block off circuit 
5.9 -- all-weather drinking fountain at Sunrise Hills Road
6.3 -- cross under Dulles Toll Road
6.7 -- cross Buckthorne Lane
7.1 -- cross Hunter Mill Road
7.3 -- stay left on horse trail, left at Tamarack Park sign.
7.4 -- athletic field -- trail resumes at far corner of field, behind pine tree;
7.45 -- turns left, back toward Difficult Run
7.8 -- cross small stream on foot bridge
7.9 -- descend bluff on gradual decline
8.2 -- hard right turn below first houses on right; cross stream
8.3 -- cross Difficult Run on "fair-weather crossing" trail becomes muddy
8.35 -- cross streamlet on plank, bear left, through dirt-bike area, heading toward Toll Road
8.5 -- cross under Dulles Toll Road
8.6 -- shallow right onto old gravel trail, going slightly uphill.
8.7 -- left on asphalt path. Stay left.
8.9 -- Cross Brown’s Mill Road, on bridge over Difficult Run
8.9 -- hard right (across guard-rail) to gravel road. Stay on gravel road for .4 miles.
9.3 -- At three-slat fence, left across planks to mud-or-dirt path
9.9 -- trail emerges onto Carper Farm Way. Turn right
9.95 -- cross Leesburg Pike at traffic light
10.05 -- Colvin Run Road to finish
See the cue sheet for this hike in the clockwise direction