What is Marshall Lake?
Marshall Lake is what the plateau’s lakes mostly are when nobody dams them: a shallow basin on Anderson Mesa at 7,138 feet that fills in wet years, shrinks to a marsh in normal ones and disappears in drought. Arizona Game and Fish and Ducks Unlimited manage it for waterfowl, which is why the northwest shore is closed to vehicles and the whole lake is fenced off with log barriers. Coots and ducks rest here on migration, osprey hunt it in summer, bald eagles winter here, and the elk herd on Anderson Mesa treats the meadow as its evening commute.
For a Scottsdale camper the point is the forest on the east side of the road. It is free dispersed camping in big ponderosa with a view across the marsh, nine miles from a Flagstaff grocery store, with a 14-day limit and nothing else: no toilet, no water, no table, no host. The Arizona Trail passes through on its way from Walnut Canyon to Mormon Lake, so you will see thru-hikers in spring and fall, and it makes a good out-and-back walk along the mesa in either direction. It is for self-contained campers who want quiet pines, elk at dusk and a dark sky, and who arrive with their own toilet plan; it is not for anyone who needs a tap or a trailer pad, or who wants a lake they can count on.
What you get is a free night in tall pines with wildlife walking past and the darkest sky near Flagstaff. What you do not get is any facility whatsoever, a dry road after rain, or, some years, a lake.
How to camp Marshall Lake right
Pay nothing, follow the rules. Dispersed camping, first come, no reservation, 14 days. Camp on the forest side of FR 128, not beside the lake; vehicles are barred from the lake area and the northwest shore by fencing. Respect it, because the alternative is a seasonal closure that ends camping here for everyone. Groups and anything commercial need a permit from the Flagstaff Ranger District.
Get there. Loop 101 north to I-17, I-17 north to exit 339 (Lake Mary Road), then Lake Mary Road southeast about 7 miles past the I-17 exit (9 from town) to Forest Road 128 on the left, signed for Marshall Lake. FR 128 climbs onto the mesa for about 3 miles; the first two are graded, the last mile or so is unpaved dirt that is fine dry and impassable wet. About 2 hours 20 minutes from Old Town. The dispersed sites begin in the last mile before the lake; the road ends at a small primitive launch on the east shore. Do not drive all the way to the water looking for a site; the good ones are back in the trees along that last mile, and most people grab the first open pull-in and stop.
Pick the season. FR 128 closes for the winter and the forest treats Marshall Lake as open from early May to mid-October. June and September are ideal. Monsoon afternoons in July and August turn the road to clay and the mesa into a lightning rod; be in camp, not on the trail, by early afternoon. If it has rained in the last two days, park on the firm ground back toward Lake Mary Road and walk in. Fire restrictions are routine in May and June; check the forest’s hotline before you build one, and keep it in an existing ring.
Water and toilets. None. Bring all your water and a shovel or wag bag; the Forest Service lists no restrooms, no potable water and no trash service, and is watching this area closely for exactly that reason. The nearest flush toilet is in Flagstaff. Leave No Trace is not a slogan here; it is the condition of the place staying open.
Boats and fishing. One electric motor or a single gas motor of 10 horsepower, launched from the primitive ramp when there is water. Game and Fish stocks trout only when levels allow.
Watch the elk and the sky. The elk come to the meadow between sunset and dark, so sit still and face east. After dark, the mesa is one of the darkest places within a day of Phoenix; see the stargazing guide.
Dogs and horses. Dogs on leash; horses and pack animals are allowed, unusually for this area.
Skip it if there is no lake this year and you want water and a toilet. Lakeview is ten minutes back down the road for $30, Canyon Vista is the trailhead campground at the other end of Passage 31, and the Rim Road has free pine camping with a view instead of a marsh.
A marsh kept for ducks on a mesa kept for telescopes
Anderson Mesa is a flat lava-capped bench between 6,200 and 7,200 feet, twenty miles long, east of Lake Mary and north of Mormon Lake, and its lakes are not reservoirs. They are shallow depressions in the basalt that hold snowmelt until it evaporates or soaks away, which is why Marshall Lake can be a mile of open water one June and a dry meadow the next. The Sinagua farmed the country around the San Francisco Peaks and built their homes in Walnut Canyon, directly below the mesa’s north edge, between about 1100 and 1250; the Navajo, who came later, call the mesa Hosh Dikʼání. The Forest Service does not publish where the name Marshall came from, and we did not find a source that does.
The federal government took the mesa with the rest of the plateau when the San Francisco Mountains Forest Reserve was created in 1898 and Theodore Roosevelt consolidated the Coconino National Forest on July 2, 1908. The road came for water: Timothy Riordan dammed Walnut Creek at the foot of the mesa in 1904 to make Lower Lake Mary for Flagstaff and his lumber mills, and Lake Mary Road followed the shore, which is how Forest Road 128 came to leave the pavement nine miles from town.
The mesa’s modern life began with astronomers. Lowell Observatory, which had discovered Pluto from Mars Hill in 1930, needed darker sky than a growing Flagstaff could offer and opened its Anderson Mesa Station in 1959, a few miles from the lake across flat, high, dry ground with no lights. The U.S. Naval Observatory followed in 1992 with the Navy Precision Optical Interferometer, choosing the mesa in part because it is so flat. The telescopes are why this remains one of the darkest places within a day’s drive of Phoenix, and why Flagstaff’s lighting ordinances reach out here.
The lake itself is managed for a different constituency. Arizona Game and Fish and Ducks Unlimited run it as waterfowl habitat, a rest stop for coots and ducks on migration and a nesting marsh in wet years, with the northwest shore closed to vehicles and log barriers across every track to the water; Game and Fish stocks trout when the water is deep enough, and the Forest Service page says plainly that in dry years the lake may disappear. Then the hikers arrived. Dale Shewalter, a Flagstaff schoolteacher, proposed a border-to-border Arizona Trail in 1985; the Arizona Trail Association incorporated in 1994 and chose Marshall Lake as the point where the trail steps off Anderson Mesa into Walnut Canyon toward Fisher Point and Flagstaff. Congress made it a National Scenic Trail on March 30, 2009, the route was declared complete on December 16, 2011, and the lake became the boundary of Passages 31 and 32, the place thru-hikers camp before their Flagstaff resupply. In 2022, a year the lake went bone dry, the association rerouted Passage 31 north of Fisher Point onto new singletrack. The campers followed the trail, the Forest Service noticed the toilet paper, and the agency’s close attention to this strip of pines is the direct result.
Why it matters
Marshall Lake is a plain lesson in what a plateau lake is: a puddle on lava that a wet winter fills and a dry one empties, managed by three agencies for ducks, trout and dark sky, and discovered by campers only because a national trail happens to drop off the mesa here. It explains Flagstaff’s lakes better than the dammed ones do. For a Scottsdale camper the verdict is honest rather than enthusiastic. It is a free, quiet, beautiful night in big pines with elk walking past and the Milky Way overhead, and it has nothing at all, so bring the toilet plan, the water and the willingness to walk the last mile if it has rained. Go in June or September, camp back in the trees, and leave the place as empty as you found it.