The swim beach at Tally Lake is the day-use area of Tally Lake Campground, a Flathead National Forest recreation site on the Tally Lake Ranger District. It sits at the northwest end of Tally Lake, a 1,211-acre natural lake in Flathead County that Montana Fish, Wildlife and Parks has surveyed at 495 feet deep, the deepest natural lake in the state. Forested ridges rise straight out of the water on most sides, and the campground occupies a flat of larch and Douglas fir where Logan Creek comes in.

The lake is about 17 road miles northwest of Whitefish. Recreation.gov and the concessionaire give this route: take US 93 north from Whitefish for 4 miles, turn left on Twin Bridges Road for 1.4 miles, stay right on Twin Bridges Road at the Tally Lake sign for another mile, turn left on Farm to Market Road for 2 miles, then turn right onto Tally Lake Road. The last 9 miles are gravel and dirt. Day-use parking is inside the campground near the boat ramp, with a short walk to the grass and the beach. The Forest Service says the road is not plowed in winter.

The swim area is a gravel and small-cobble beach in front of a large mowed lawn, with a buoy line marking off the swimming zone. Forest Service photos show kids wading close to shore inside the buoys, but this is a very deep lake overall, so keep weak swimmers near the beach. Because the lake is stained brown by tannins it absorbs sun and gets fairly warm by late summer, warmer than most deep lakes in the valley. There is no current. No lifeguard service is listed by the Forest Service or the concessionaire, so swimming is at your own risk. A changing area, vault toilets, potable water and picnic tables are close to the beach.

Day use is not free. The Flathead National Forest's April 2025 campground directory lists a $6 day-use fee per vehicle at Tally Lake, and a $50 annual season pass covers concession-run day-use sites across the forest (two passes for $80 if a second family vehicle is present). Interagency Senior and Access pass holders get 50 percent off day-use fees; the Interagency Annual pass does not apply. Flathead Valley Campgrounds, which runs the site for the Forest Service under permit, operates it from about mid-May to mid-September, weather permitting. Separate day-use hours are not published; campground quiet hours are 10 p.m. to 6 a.m.

Dogs are not allowed on the beach, though leashed pets are fine elsewhere in the campground. Motorboats and water skiers share the lake, so stay inside the buoys. The Wikipedia entry notes cliff jumping elsewhere on the lake; the cliffs are not part of the managed site and nobody checks the water depth below them. This is grizzly country, and a forest-wide food storage order requires attractants to be kept in a vehicle or bear-resistant container whenever they are not in use. Boats launched here must stop at Montana aquatic invasive species inspection stations on the way in.

Beyond swimming, the campground has 40 sites (some reservable through Recreation.gov), a group site, an open-air pavilion, a volleyball court and an accessible fishing dock. Kayaks and paddleboards rent for $10 an hour and canoes for $15 an hour at the campground. Anglers fish for kokanee, trout, whitefish, perch and northern pike. A trail off the north shore road climbs about a mile to a viewpoint over the lake.