• Marshall Lake Trailhead to Interstate 40


  • 17.9 miles

Southern Trailhead: Marshall Lake Trailhead


From Flagstaff, take the Lake Mary Road exit (339) off I-17 for 9 miles, then turn left (east) on FR 128 at the sign for Marshall Lake. Pass the observatory turnoff, then at 2.2 miles turn left before Marshall Lake (more of a marsh) and park at the AZT sign on the left. If you are coming from the south on Lake Mary Road, the Marshall Lake turnoff is 7.5 miles north of Pine Grove Campground.

Northern Access Point: I-40, Cosnino Road Exit

GPS Coordinates: 35.20249° N, 111.48559° W Note: this point is located across a private property boundary from the I-40 frontage road. No parking is allowed along the frontage road.


Currently, there is not direct access to the Northern boundary of this passage. The closest access to the south 4 miles south at Old Walnut Canyon Road: From Flagstaff, follow I-40 east and take exit 204 toward Walnut Canyon. Follow the paved Walnut Canyon Road (FR 622) south for 2.5 mi to Old Walnut Canyon Rd (FR 303). Turn right. The trailhead is about 1.7 mi west on the left (south) side of the road. There is room for horse trailers.

Trail Route Description

From the Marshall Lake Trailhead the trail heads mostly west across flat forest land. It passes through a gate, drops into a small canyon, crosses a road and climbs out the other side. The trail crosses FR 128B and then descends steeply into Lower Walnut Canyon. It passes the Sandy’s Canyon Trail junction, turns to the right and goes up the canyon. The trail forks to the right and climbs steeply out of Walnut Canyon at Fisher Point. Once on top it passes the Fisher Point Trail junction and then crosses FR 301. The trail parallels Walnut Canyon and passes another trail junction. After two more junctions the trail descends down into a tributary of Walnut Canyon. It follows the canyon for a short ways and then climbs steeply out of it. From here the trail joins a two-track and then heads north up to FR 303, which is a trailhead. The trail stays north of the Walnut Canyon National Monument until it crosses the entrance road. It then turns to the north and works its way down to Interstate 40.

About 6.4 miles from the south end of this passage the AZT splits. This passage and passage 32 continue in a wide arch through many gentle miles of the stunning Arizona high country around Flagstaff. Passage 33 takes users into town. Know that shopping opportunities are available on both routes, the bypass route crosses highway 89 less than two miles east of a large mall and motels, and cab fares in town are quite reasonable.


  • Moderate



There are reliable water sources on this passage at the two wildlife water tanks. There is water in the city of Flagstaff and in Walnut Canyon National Monument.  Check the online Arizona Trail Water Report for current information at https://aztrail.org/explore/water-sources/.


  • All water along this passage should be purified prior to use.


  • USGS Topographic Maps: Lower Lake Mary, Flagstaff East and Winona.
  • Coconino National Forest – Visitors Guide.
  • Coconino National Forest – Recreational Opportunity Guide.
  • Coconino National Forest map.
  • BLM Information Center maps.

For more information

Current Passage Info

Camping and Campfire Restrictions Near Flagstaff

Camping and Campfire Restrictions Near Flagstaff

Due to extreme fire danger, the Coconino National Forest has issued a closure order for camping and campfires near Flagstaff. There is no overnight camping permitted along the following passages and mileages (using the FarOut app): Passage 31 (Walnut Canyon) from Sandys Canyon Trail (mile 554.8) to Walnut Canyon Road (mile 565.2) Passage 32 (Elden Mountain) from Railroad Tracks (mile 567.5) to Heart Trail (mile 576.0) Passage 33 (Flagstaff Urban Route) from Sandys Canyon (mile 0) to Fort Valley Trails (mile 12.8) Click here to view the current Camping and Fire Restriction Order.  
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Flickr Photos

Photos from the Arizona Trail Association’s Flickr galleries, for this specific passage. View the entire Flickr account.

[AFG_gallery id=’32’]