Crystal Lake Campground
Moore, Montana · on Big Rock Creek · Lewis & Clark National Forest
Verified · 5 independent sources · top-verified
- WATER
- lake
- FALLS
- Waterfall on site
- ACCESS
- Designated swim area
- FEE
- $10
- SEASON
- Best in summer
About Crystal Lake Campground
Crystal Lake is a small, shallow 45-acre mountain lake at 5,700 feet elevation in the Big Snowy Mountains, within the Helena-Lewis and Clark National Forest south of Lewistown/Moore, Montana. It is a developed USFS recreation site with an established campground, and swimming, fishing, and non-motorized boating are all official uses of the lake, so this mountain swimming hole is a fully sanctioned lake to swim in.
The lake sits in a limestone basin in the shadow of Mt. Harlow, surrounded by the Big Snowy Mountains, an isolated 'island range' rising out of the Montana prairie. Nearby features include Crystal Cascades, a roughly 100-foot waterfall, and the Snowy Mountain Ice Caves, both reachable via side trails from the lake.
Swimming at Crystal Lake Campground
Swimming is an officially recognized, popular family activity at Crystal Lake, especially in summer. The lake is shallow (maximum depth about 15 feet) with clear water, and levels drop through the season as water seeps through the limestone bedrock, leaving it 'little more than a large shallow pond' by fall in some years. This makes the spot well suited to families and casual swimmers rather than deep-water swimming.
How to get to this swimming hole
From Lewistown, MT, take US Highway 87 west/north about 8.7-9 miles to the Forest Access sign, then turn onto Crystal Lake Road (partly dirt, partly paved) and continue roughly 22 miles to the lake; the final nearly 6 miles are single-lane, steep, and twisty in places.
Parking: Campground and day-use parking available on site; the group campsite has a separate gated parking area (gate access code obtainable by calling ahead).
The hike in
Lake Loop Trail (Trail #404)
The swimming/boating area is directly drive-up from the campground and day-use parking -- no hike is needed to reach the water. Several optional trails radiate from the lake for visitors who want to explore further: the easy Lake Loop Trail #404 (under 2 miles, minimal elevation change, several benches overlooking the water) circles the shoreline; the Crystal Cascades Trail (~3.5 mi, ~1,000 ft gain) leads to a roughly 100-ft waterfall; the Ice Caves Trail (~5 mi, ~2,200 ft gain) reaches the Snowy Mountain Ice Caves; Grand View Trail (~3.5 mi, ~1,000 ft gain) and Promontory Peak (~1.25 mi, ~400 ft gain) reach overlooks; and the full 12-mile Crystal Lake National Recreation Trail loops the high country above the lake with a steep 2,000 ft climb in its first 3 miles.
None of these trails are prerequisites for swimming; they're bonus hikes for visitors already camped or parked at the lake.
Plan your visit
Bringing kids
OK with supervision
Widely described as a popular family swimming spot (visitmt.com calls it 'an excellent family campground') thanks to a shallow, gently sloped lake bottom that visitmt.com notes reduces drowning risk as water drops seasonally. That said, there are no lifeguards, water reaches roughly 15 ft in the deeper parts, the lake bottom can turn soft/muddy as levels drop later in summer, and bears are common in the area (a food-storage order is in effect), so supervision and normal backcountry-lake precautions are warranted.
Parking
Lot
Parking at the campground/day-use area and at the group campsite's separate gated lot (access code must be arranged by calling ahead). No standalone day-use parking fee is documented; individual campsites are self-pay at roughly $20/night, but simply parking to swim without camping is not clearly addressed in any source found.
Restrooms
Yes
Vault toilets at the campground, including at least one handicap-accessible unit (USFS, thedyrt.com note '4 or 5 covered toilets throughout campground area'); a separate outhouse sits next to the parking area serving the group campsite (Recreation.gov).
Water clarity
Varies with season and flow
A camper review on The Dyrt describes the lake as 'so peaceful and clear,' and discoveringmontana.com notes the shallow water is clear enough to see stocked trout. However, multiple sources note the lake drains through its porous limestone basin over the season, dropping water levels and leaving it 'little more than a large shallow pond' with likely murkier, warmer conditions by late summer/fall (montanahikes.com, USFS).
Hours
Day-use area is generally accessible year-round when the access road is clear of snow; the campground itself operates roughly June 2 through late October, with exact open/close dates shifting year to year based on snowfall (USFS, thedyrt.com).
On the water
Restrictions: Non-motorized craft only -- gas-powered motors are prohibited (discoveringmontana.com); a boat launch for non-motorized boats is provided at the campground (USFS, montanahikes.com describes it as 'open to all types of non-motorized boating' with a boat ramp/beach area).
Given the lake's small size (~45 acres) and shallow depth (~15 ft max, shrinking further through the season), this suits casual paddling rather than serious touring or motorized watersports.
What regulars say
Visitor reports from campers consistently flag the roughly 20 miles of gravel plus about 6 miles of narrow, single-lane paved access road, with steep drop-offs on the final stretch, as the main hazard getting to the lake, more so than the water itself. Visitors also note recent beetle-kill tree removal has stripped shade and privacy from many campsites, and that the group campsite's gated parking area requires calling ahead for an access code.
Crystal Lake Campground: FAQ
Does Crystal Lake Campground charge a fee?
Single campsite overnight fee around $10-$20 per night (self-serve payment, first-come first-served, no reservations for individual sites); cabin rental about $60/night.
Is Crystal Lake Campground kid friendly?
Widely described as a popular family swimming spot (visitmt.com calls it 'an excellent family campground') thanks to a shallow, gently sloped lake bottom that visitmt.com notes reduces drowning risk as water drops seasonally. That said, there are no lifeguards, water reaches roughly 15 ft in the deeper parts, the lake bottom can turn soft/muddy as levels drop later in summer, and bears are common in the area (a food-storage order is in effect), so supervision and normal backcountry-lake precautions are warranted.
Do I need to hike to reach Crystal Lake Campground?
No significant hike is required. The swimming area is close to parking and access.
Where do I park for Crystal Lake Campground?
Parking at the campground/day-use area and at the group campsite's separate gated lot (access code must be arranged by calling ahead). No standalone day-use parking fee is documented; individual campsites are self-pay at roughly $20/night, but simply parking to swim without camping is not clearly addressed in any source found.
Can I bring a kayak or paddleboard to Crystal Lake Campground?
Given the lake's small size (~45 acres) and shallow depth (~15 ft max, shrinking further through the season), this suits casual paddling rather than serious touring or motorized watersports.
When is the best time to visit Crystal Lake Campground?
Mid-June through Labor Day/late October for the campground; access road typically closed by snow from late fall until early June. Water levels and swimming conditions are best in early-to-mid summer before seasonal drawdown.
What are the rules at Crystal Lake Campground?
Maximum stay of 16 consecutive days; leashed dogs allowed, horses prohibited; motorized OHVs restricted to campground roads; food storage order in effect March 1-December 1 (bear precautions); motorized boats prohibited on the lake, non-motorized boating/canoeing/kayaking only; valid Montana fishing license required to fish.
What water body is Crystal Lake Campground on?
Crystal Lake Campground is on Big Rock Creek, a natural lake verified in USGS hydrography data.
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