Flathead Lake

Flathead Lake in Montana

The center of the lake is at 47.9017, -114.1042. Surface elevation is about 2,894 feet. It reaches roughly 371 feet at its deepest.

Public access at Flathead Lake covers 3 named swimming spots. Long Beach, Swan Lake Swimming Site and Flathead National Forest are on the list. These come from Recreation.gov (RIDB), USDA Forest Service and USGS GNIS. Fees and opening dates are set by each park, not by the agency that runs the water.

Station 12371550, Flathead Lake at Polson MT, publishes the water surface elevation used here. The last value stored here, 2,893.04 ft, is from 2026-09-09. Over the record shown on the level page the gauge has moved between 2,886.35 ft and 2,893.15 ft (low on 2026-03-20, high on 2026-07-02). Beach width and ramp access both move with the pool, so the number above is worth a look first.

Most Montana day-use areas open for the summer season and close outside it. Water quality is monitored unevenly on inland lakes, so posted notices are the most reliable guide. No public sensor reports water temperature at Flathead Lake, so the panel shows air temperature and wind.

If Flathead Lake is busy, the nearest alternatives here are Hungry Horse Reservoir (Montana, 21 mi), Whitefish Lake (Montana, 40 mi) and Lake McDonald (Montana, 47 mi). Montana has 21 lakes on this site in total.