A natural glacial lake, and yet Flathead's top ten feet answer to a calendar as much as to weather: drawn down each spring toward mid-April, refilled by mid-June, held near full through Labor Day, then lowered again each fall. A tribal corporation keeps that schedule — owned by the people whose reservation reaches into the water, its boundary splitting the lake almost exactly in two, state authority to the north, tribal governance to the south. A license bought for the southern half pays for fishing only; shore access on tribal land takes a separate permit. Mid-June surface water still sits near 56 degrees, too cold for the swimming the postcards promise, and the shallows at Yellow Bay are rounded stone underfoot, not sand. Nights stay quiet on both shores, though a two-lane road carries through until the traffic thins. East-shore cherry stands line the road each summer, kept alive by a lake too large to warm or cool on cue.
curator · lake-level · as of Sep 3, 2026
The facts
- Surface area 494.7 km² usgs-3dhp · lake-level · as of Jun 2, 2026
- Nearest town Rollins · 5.4 km osm-overpass · lake-level · as of Jun 2, 2026
- Bird species (within 25 mi) 211 ebird-api-v2 · lake-level · as of Jun 2, 2026
- Bird diversity index 0.9 ebird-api-v2 · lake-level · as of Jun 2, 2026
- Median home value $522,967 census-acs-2024-b25077 · block-group-level · as of Jun 2, 2026
- Water clarity Glass-clear curator · lake-level · as of Sep 3, 2026
- Night sky Darkest skies viirs-black-marble-vnp46a4 · lake-level · as of Sep 3, 2026
- Surroundings Resort — a shoreline built for visitors curator · lake-level · as of Sep 3, 2026
- Water origin Natural lake with a regulated outlet curator · lake-level · as of Sep 3, 2026
In more detail
- Climate
- four-season; cold winters (~30°F mean), mild summers (~65°F); ~22 in precip/yr noaa-normals-1991-2020-descriptor · lake-level · as of Jun 2, 2026
- Public access
- Flathead Lake has extensive public access on the north/majority of shoreline via Montana FWP's Flathead Lake State Park (six mainland/island units: Big Arm, Finley Point, Wayfarers, West Shore, Yellow Bay, Wild Horse Island) plus separate FWP fishing access sites (Bigfork, Elmo, Juniper Beach, Sportsman's Bridge, Walstad). The southern half of the lake lies within the Flathead Indian Reservation, where CSKT-owned shoreline is private tribal land requiring a non-member recreation/conservation permit for land-based access; fishing reservation waters additionally requires a CSKT fishing license. Boat launches exist at West Shore, Yellow Bay, and Finley Point (slips); Yellow Bay has a public swim beach. Fees/permits: Montana State Parks units: standard day-use/camping fees, reservations via montanastateparks.reserveamerica.com. CSKT Flathead Reservation (south half of lake): non-member recreation/conservation permit required for tribal land access, additional tribal fishing license required to fish reservation waters; exact fee schedule not confirmed from a fetched primary source (see curator_read_needed).. Sources: fwp.mt.gov (fetched 2026-07-12); cskt.org (fetched 2026-07-12); mackdays.com (search-extraction 2026-07-12); montanasflatheadlake.com (search-extraction 2026-07-12). curated-web-harvest · lake-level · as of Jul 12, 2026
- Dogs and pets
- medium — 4 dog parks within 25 mi (OSM); state rule: In developed areas of Montana state parks, pets must be physically restrained or on a leash no longer than 8 feet at all times unless otherwise posted; pets are prohibited on swimming beaches and any posted-restricted area. A few parks ban pets entirely or seasonally (Lewis and Clark Caverns cave, Frenchtown Pond, Wild Horse Island, Smith River floats, Spring Meadow Lake Apr16-Oct14). (Montana State Parks Public Use Rules, ARM 12.8.801 et seq. (Montana FWP), fetched 2026-07-12); Pets are not permitted on Wild Horse Island (a Flathead Lake State Park unit) to protect wildlife viewing opportunities. (fwp.mt.gov, fetched 2026-07-12); Statewide state-park rule applies at the mainland Flathead Lake State Park units: pets are not permitted on swimming beaches (e.g., Yellow Bay's beach), otherwise leash to 8 feet in developed areas. (fwp.mt.gov, fetched 2026-07-12) curated-web-harvest · lake-level · as of Jul 12, 2026
- Property tax
- 0.61% ACS effective-rate proxy (2024 ACS 5-year; Lake County anchor: $2,561 median real-estate taxes paid ÷ $421,800 median owner-occupied home value; Montana proxy 0.72%, -0.11 percentage points). census-acs-2024-property-tax · county-level · as of Dec 31, 2024
Where it’s heading
Stable hand-rated for v0.1 · lake-level · as of Sep 3, 2026
Stable by the mini-pass criterion: the sheet carries no documented growth data for Lake or Flathead County (no permit, population or listing-velocity source was harvested), and the place-scale signals present are conditions, not trajectories — the 2023 low-water summer (FERC later found the operator within its license), the federal/state 'impaired' nutrient listing and the fall-2025 PFAS detection (FLBS), and 'hit or miss' cherry harvests (Flathead Beacon 2026). Rising-candidate if Flathead County (Kalispell/Bigfork north shore) growth is documented at Census or permit grade — a curator harvest target.