Flathead Lake

State: Montana. Type: natural freshwater lake spanning Lake and Flathead counties in the state's northwest. Size: about 197 square miles (roughly 30 miles long, 16 miles wide), one of the largest natural freshwater lakes by surface area in the western United States. Maximum depth: 370.7 feet; average depth 164.7 feet. Flathead Lake State Park comprises seven units around the lake with a combined 140 campsites.

Flathead Lake fills a broad valley in northwest Montana about seven miles south of Kalispell, ringed by the towns of Polson, Bigfork, Lakeside and Somers. Originally called Salish Lake, it takes its present name from the Salish Indians, whose name arose from a historical mistranslation of sign language by early European explorers; the 1855 Treaty of Hellgate later established the Flathead Reservation encompassing much of the lake. The valley's surprisingly mild climate, for a region this far north and inland, supports cherry orchards along the lake's east shore and vineyards to the west. Ecologically, the lake has changed dramatically since non-native opossum shrimp were introduced, which shifted the fishery toward lake trout and contributed to the loss of kokanee salmon populations, while native bull trout and cutthroat trout persist. Recreation centers on Flathead Lake State Park's seven units, U.S. Route 93 along the west shore and Montana Highway 35 along the east, and the Seliš Ksanka Qlispe' Dam (formerly Kerr Dam), which manages water levels for power, recreation and irrigation.

Flathead Lake sits in Lake and Flathead counties in northwestern Montana, about seven miles south of Kalispell, with Polson at its southern end and Bigfork near its northeast shore. U.S. Route 93 runs along the west shore and Montana Highway 35 along the east shore.

The Flathead Valley has a notably mild climate for its northern, inland location, which supports orchard and vineyard agriculture around the lake. Summers are warm and popular for water recreation, while winters are colder, with the lake's large water volume moderating temperature extremes somewhat compared with surrounding areas.

Summer is the primary season for swimming, boating and lake-based recreation, when park campgrounds and cherry stands along the east shore are in full operation. Late spring and early fall offer milder crowds while still allowing hiking and sightseeing around the lake's shoreline towns.

The lake was originally known as Salish Lake, later renamed for the Salish Indians after early European explorers misread native sign language and coined the term "Flathead Indians." The 1855 Treaty of Hellgate established the Flathead Reservation, which encompasses much of the lake's southern half. In the 20th century, the introduction of non-native opossum shrimp dramatically altered the lake's ecosystem, causing lake trout to dominate the fishery and contributing to the extirpation of kokanee salmon, a major shift from earlier native fish populations of bull trout and cutthroat trout.

Swimming, boating, kayaking and fishing are the lake's main draws, supported by Flathead Lake State Park's seven units around the shoreline. Big Arm offers an archery range and camping, West Shore offers kayak rentals, and Wild Horse Island, the largest island unit at 2,160 acres, provides hiking and wildlife watching. Cherry-picking and orchard visits along the east shore, and vineyard visits on the west shore, are popular seasonal activities tied to the valley's mild microclimate.

Flathead Lake State Park's seven units, Big Arm, Finley Point, Wayfarers, West Shore, Wild Horse Island, Yellow Bay and the Flathead Lake Islands unit, are the lake's main protected recreation areas. Bigfork, on the northeast shore, is known for its arts scene and summer playhouse; Polson anchors the lake's southern end.

Glacier Park International Airport, near Kalispell, is the closest commercial airport, roughly a short drive from the lake's north end. U.S. Route 93 provides the main road access along the west shore, connecting Kalispell, Lakeside and Polson, while Montana Highway 35 serves the east shore towns including Bigfork and Yellow Bay.

Flathead Lake State Park's units generally operate on a seasonal basis, with fullest services in summer; some individual units, such as Yellow Bay, take camping on a first-come, first-served basis. Confirm current unit-by-unit hours and seasonal openings on the Montana Fish, Wildlife & Parks website before visiting.

Camping reservations for the state park's units are handled through Montana State Parks' reservation system at 855-922-6768 or montanastateparks.reserveamerica.com; specific day-use and camping fee amounts were not confirmed in the sources reviewed and should be checked directly on fwp.mt.gov before a visit. Recreation units within the Flathead Reservation portion of the lake require tribal recreation permits and fishing licenses for waters outside the state park.

A half-day to full day suits a single stop such as swimming or a state park unit visit, while a multi-day stay allows time to explore several shoreline towns, go boating, and visit orchards or Wild Horse Island.

The lakeside towns of Polson, Bigfork, Lakeside and Somers offer a range of lodging from cabins and lakefront motels to vacation rentals, alongside camping at the state park's seven units (140 campsites total, including yurts at Big Arm). Kalispell, a short drive north, adds a wider selection of hotel chains.

Bigfork and Polson both have established small-town dining scenes with lake-view restaurants and casual cafes; roadside cherry stands are a distinctive seasonal food draw along the east shore in summer. Kalispell offers a broader range of dining options for those staying closer to the airport.

Kalispell and Whitefish sit a short drive to the north, both serving as gateways to Glacier National Park, which lies further north still. Bigfork's arts district and the Mission Mountains to the east are popular nearby stops for lake visitors.

Glacier Park International Airport near Kalispell is the nearest commercial airport. A rental car is the most practical way to reach and get around the lake, since its shoreline towns are spread along US-93 and MT-35 without a comprehensive transit network.

Sudden strong winds can create rough water conditions on the lake, so boaters should check forecasts before heading out. Cold water temperatures, even in summer, can pose a hypersaturation/hypothermia risk for swimmers venturing far from shore. Tribal recreation permits are required in parts of the lake within the Flathead Reservation, so check requirements before fishing or recreating outside the state park units. For any emergency, dial 911.

Sunscreen, a hat and swimwear for lake days, a life jacket for boating or paddling, and a light jacket for cooler evenings are all worth packing. Cash or a card for cherry stands and small-town shops along the shore is also handy.

Reserve state park campsites well ahead for summer weekends, since the park's seven units have a combined total of only 140 campsites. Check whether your planned activity falls within the Flathead Reservation portion of the lake, since a tribal recreation permit may be required there in addition to, or instead of, standard state park fees.

Dial 911 for any emergency. For Flathead Lake State Park camping inquiries, Montana State Parks' reservation line is 855-922-6768; the Yellow Bay unit can also be reached directly at 406-837-3041, ext. 0, per Montana Fish, Wildlife & Parks.

Flathead Lake State Park (Montana Fish, Wildlife & Parks) - https://fwp.mt.gov/stateparks/flathead-lake/

This section is being updated and will be available shortly.

This section is being updated and will be available shortly.

This section is being updated and will be available shortly.