Dog Lake (Big Cottonwood Canyon)

A moderate out-and-back of about 5.5 miles round trip (roughly 1,470 feet of gain) up the Mill D North Fork Trail (#158) on the north side of Big Cottonwood Canyon to a small, tree-rimmed lake perched near the divide between Big Cottonwood and Mill Creek canyons at roughly 8,733 feet. The route climbs through aspen and conifer, passes a spring, and reaches a signed junction where the right fork continues to Desolation Lake — a common, longer add-on. Despite the name, dogs are banned here: the entire canyon is Salt Lake City's protected drinking-water watershed, where no dogs (or other domestic animals) and no swimming or wading are allowed, and the rules are enforced. The dog-friendly way to reach the lake is from the Mill Creek Canyon side (the Big Water trailhead) — an entirely separate canyon and trail. The trail also forms part of the Wasatch Crest mountain-bike corridor, with the Mill D turnoff a key junction on the ridgeline ride.

Quick stats

Distance

5.5 mi round trip

Elevation gain

1469 ft

Time

3–3.5 hrs

Difficulty

Moderate

Dogs

Not allowed

Fee

Day-use parking fee

Best months

Jul, Aug, Sep

Getting there & parking

From Salt Lake City, take I-215 to the 6200 South exit and follow Big Cottonwood Canyon Road (SR-190) up-canyon about 8.8 to 9 miles to the Mill D North Fork / Cardiff Fork area near Spruces Campground — roughly 30 to 40 minutes from downtown. The Mill D North Fork trailhead is on the north (left) side of the road; the lot is small and fills early on summer weekends, so arrive before 9 a.m. or come midweek. A standard passenger car is fine. As of December 1, 2024 this is a fee lot — bring a valid Forest Service or interagency pass.

As of December 1, 2024 the Mill D / Cardiff Fork trailhead is a Forest Service recreation fee area. A valid Forest Service Recreation Pass (Uinta-Wasatch-Cache 3-day, 7-day, or annual) or an America the Beautiful interagency pass is required for all vehicles parking at the lot. Passes are sold via recreation.gov, the UWC Salt Lake Ranger District office, and Salt Lake City REI; compliance is checked by hang-tag/dashboard receipt or license plate. Confirm the current fee amount at the trailhead — the program is recent.

Know before you go

No dogs. Dogs are banned here despite the lake's name. All of Big Cottonwood Canyon is Salt Lake City's protected drinking-water watershed, where no domestic animals are permitted — Forest Service signage notes pets are not allowed at all, not even left in your vehicle — and the rules are enforced with fines. The dog-friendly route to the lake is the entirely separate Mill Creek Canyon approach (the Big Water trailhead), a different canyon outside this watershed. The lake straddles the Mill Creek / Big Cottonwood divide and is reached from both sides; only the Mill Creek side permits dogs. Do not confuse the two approaches.

No hiking permit required. A Forest Service day-use parking fee does apply — see Getting there & parking above.

The route

Steady, moderate grade through forest with some rocky sections. Distance and gain vary by source and exact turnaround — AllTrails lists about 5.5 mi / 1,469 ft, while the USFS describes Trail #158 as about 2.6 mi to the saddle/junction.

• 0 mi · Mill D North Fork Trailhead — Start at about 7,292 ft on the north side of SR-190, roughly 8.8 to 9 mi up Big Cottonwood Canyon near Spruces Campground. Fee parking.
• 0.9 mi · Beartrap Fork junction (variant) — Alternate, roughly parallel approach via Beartrap Fork; commonly used when linking Dog Lake with Desolation Lake. Junction mileage is approximate.
• 1.8 mi · Spring and signed Desolation Lake junction — Past a spring, a signed junction splits: right (east) heads to Desolation Lake, the main trail continues to Dog Lake.
• 2.7 mi · Dog Lake — Small lake near the Big Cottonwood / Mill Creek divide at about 8,733 ft. Turnaround for the out-and-back; loop options return via Butler Fork.

When to go

Best from mid-summer through early fall. Aspen color peaks in late September. The small lake basin is mosquito-heavy in early to mid-summer and the lake can run shallow and muddy. Snow lingers on the upper trail into June.

Surrounding slopes are avalanche terrain in winter, and this is not a casual winter hike without avalanche awareness and gear. Big Cottonwood Canyon Road (SR-190) requires approved snow tires or traction devices from October 1 through April 30, and avalanche control can close the road outright. Check the road status and avalanche forecast before you go.

Check current conditions before you go:

• UDOT Cottonwood Canyons road status
• Utah Avalanche Center — Salt Lake forecast

Safety & hazards

Watershed enforcement: dogs and other domestic animals are banned canyon-wide, and swimming or wading is prohibited. Violations are ticketed and fined. This is Salt Lake City's drinking-water source. The dog-friendly Dog Lake is the separate Mill Creek Canyon approach.

Surrounding slopes are avalanche terrain in winter. The area is not recommended as a casual winter hike without avalanche awareness and gear. Check the Utah Avalanche Center Salt Lake forecast before any winter or spring outing.

Big Cottonwood Canyon Road (SR-190) requires approved snow tires or traction devices from October 1 through April 30, and avalanche control can close the road. Check UDOT Cottonwood Canyons status before driving up.

Afternoon summer thunderstorms bring lightning to the open ridgeline near the crest. Start early and be off exposed ridgeline before storms build.

Mosquitoes near the lake in early to mid-summer. Bring repellent; the lake basin meadows are buggiest in July.

Wildlife & geology

The route passes through extensive quaking aspen groves mixed with spruce and fir, notable for fall color. The small subalpine lake basin supports wetland vegetation and mosquito-heavy meadows in early summer.

Wildlife you might see: mule deer, moose.

The lake sits in glacially shaped terrain near the high divide of the Wasatch Range's west slope, in a basin on the ridge separating Big Cottonwood and Mill Creek canyons.

History

Named "Dog Lake," but it ironically lies within a watershed where dogs are prohibited; the name predates current Salt Lake City watershed restrictions.

The Mill D North Fork drainage is a long-used recreation corridor and today is part of the Wasatch Crest mountain-bike route between Big Cottonwood and Mill Creek canyons.

Nearby hikes

• Desolation Lake — Big Cottonwood Canyon
• Lake Blanche — Big Cottonwood Canyon
• Donut Falls — Big Cottonwood Canyon