Flathead Lake, Montana: Vacation Guide

Flathead Lake is the largest natural body of freshwater by surface area in the western U.S., according to Montana Fish, Wildlife & Parks. It covers about 191 square miles in northwest Montana. A Flathead Lake trip comes down to three choices: which shore to base on, which state park units and islands to visit, and whether your plans cross into the Flathead Indian Reservation on the southern half of the lake, where tribal permits apply. This guide covers all three, with a shore-by-shore map at the end.

How big is Flathead Lake?

The Flathead Lake Biological Station (FLBS), the University of Montana's research station on the lake, lists these figures (FLBS lake facts):

FLBS notes that Lake Tahoe holds more water because it is deeper, and that the Great Salt Lake is larger in area but salt water.

The lake level changes through the year. Seli'š Ksanka Qlispe' Dam near Polson regulates it across about 10 feet, generally between 2,883 and 2,893 feet above sea level. If runoff allows, the lake reaches full pool, 2,893 feet, by June 15 and is typically kept within 1 foot of full pool through Labor Day (FLBS weather center). That is why summer beaches look different from fall and spring beaches.

What are the Flathead Lake State Park units?

Flathead Lake State Park has five mainland units around the lake, plus Wild Horse Island (FWP). Swimming, hiking, wildlife watching, boating and fishing are popular across the park.

• West Shore: 6 miles south of Lakeside on U.S. Highway 93, on the west side of the lake. 129 forested acres with hiking trails and a long shoreline FWP calls excellent for picnicking and swimming. Its deep-water boat launch is typically ice-free through winter. A park concessionaire rents stand-up paddleboards, kayaks and pedal boats in summer.
• Big Arm: 15 miles north of Polson on U.S. Highway 93, on Big Arm Bay on the west side. Views of the Swan and Mission ranges and Wild Horse Island, plus camping, swimming, fishing, boating and an archery range.
• Wayfarers: near Bigfork on the northeast shore. Mixed forest, wildflowers from spring to late fall, and a rocky shoreline with cliffs popular with photographers, hikers and swimmers.
• Yellow Bay: 14 miles south of Bigfork on the east shore. A wide, gravelly beach for swimming and kayaking, and a deep-water launch that is typically ice-free in winter.
• Finley Point: 12 miles north of Polson on the southeast shore, in open ponderosa pine forest, with campsites and boat slips.

Camping reservations for the units go through Montana State Parks reservations. Big Arm, Finley Point and Yellow Bay sit within the Flathead Reservation (see the permit section below).

Somers Beach State Park is a separate FWP park on the north shore. FWP acquired the 106-acre property in 2021. It is day-use only, with nearly half a mile of shoreline, and dogs must be leashed. A wide sandy beach appears when the lake is below full pool, from fall through spring (FWP Somers Beach).

Can you visit Wild Horse Island?

Yes, by your own boat, for the day. Wild Horse Island is the largest island on Flathead Lake, with a 2,160-acre state park and more than 3 miles of trails (FWP islands). FWP is clear on the rules (FWP Wild Horse Island):

• Boat access only. FWP does not provide rides or charters.
• There is no public dock. Use one of the six designated landing sites and stay off private docks.
• Day use only; camping is prohibited. Pets are not allowed.
• Groups over 15 need a special-use permit.
• Do not approach within 100 feet of any wildlife, including the horses. FWP lists bighorn sheep, mule deer, bald eagles, falcons and five wild horses on the island.
• It is bear country, and there are no food lockers on the island.
• A tribal fishing license is required to fish there.

FWP manages four other islands. Cedar Island, offshore from Rollins, has six first-come campsites. Bird, Douglas and Goose islands are closed to all use from March 1 to July 15 to protect nesting birds, and a conservation license is required to visit Cedar, Bird, Douglas and Goose (FWP islands).

Do you need a tribal permit at Flathead Lake?

On the southern half, often. The southern half of the lake is on the Flathead Indian Reservation, home of the Confederated Salish and Kootenai Tribes (Glacier Country). FWP says all recreation on tribal land outside the state parks requires a tribal recreation permit, and a tribal fishing license is required to fish the southern half of the lake (FWP). Polson, Big Arm, Elmo and Dayton are on the reservation. Check the CSKT Tribal Fish & Game page before you go.

What else is there to do on Flathead Lake?

Glacier Country lists swimming, fishing, powerboating, stand-up paddleboarding, kayaking and sailing as the main ways to spend time on the water (Glacier Country). Three planning notes:

• Boats and paddlecraft: stop at every mandatory watercraft inspection station and follow Clean. Drain. Dry. (FWP aquatic invasive species).
• Wind and waves: check the National Weather Service Flathead Lake forecast before heading out, as FWP recommends.
• Cherries: from mid-July to mid-August, orchards and fruit stands along the east shore sell Flathead cherries, and some offer u-pick (Glacier Country).

Annual events include the Bigfork Whitewater Festival, Fourth of July fireworks over the lake and the Flathead Cherry Festival. Confirm dates with the organizers before you book around them.

Flathead Lake map: what is on each shore

For a printable map, see the FLBS lake facts page. This table places the towns and parks named in this guide by shore, using FWP's own location descriptions.

Glacier Country names Polson and Bigfork as the largest lake communities, with Big Arm, Elmo, Rollins, Lakeside, Dayton and Somers as smaller stops.

Where should a group stay at Flathead Lake?

Pick a shore first, then a whole home that fits the group. Trailstead has two homes near the lake:

• The Tamarack in Lakeside, on the west side. Six bedrooms, nine beds and 4.5 baths, with overnight occupancy limited to 10, a private hot tub and sauna, a fire pit and a game room.
• The Evergreen in Somers, at the north end of the lake. Six bedrooms and 3.5 baths, a private hot tub and barrel sauna on the deck, a speakeasy and a game room. The driveway fits three vehicles plus a trailer.

Neither home is on the water. Both have no private, deeded or direct lake access. Guests reach Flathead Lake through public beaches, boat ramps, marinas and parks like the ones above. For more on choosing a base, see Choosing a Flathead Valley base.

Plan your dates

Rates and availability change by date. The booking page shows live availability and the total for your dates and group size.

Check The Tamarack's availability

FAQ

How big is Flathead Lake? About 191.5 square miles, 27.3 miles long and 15.5 miles wide at its widest, with a maximum depth of 370.7 feet, according to the Flathead Lake Biological Station.

Is Flathead Lake the largest lake in the West? Montana FWP calls it the largest natural body of freshwater by surface area in the western U.S. Lake Tahoe holds more water because it is deeper.

What are the Flathead Lake State Park units? West Shore, Big Arm, Wayfarers, Yellow Bay and Finley Point, plus Wild Horse Island. Somers Beach State Park on the north shore is a separate FWP park.

Can you visit Wild Horse Island? Yes, for the day, by your own boat. There is no public dock, camping and pets are prohibited, and groups over 15 need a permit.

Do you need a tribal permit at Flathead Lake? The southern half of the lake is on the Flathead Indian Reservation. FWP says recreation on tribal land outside the state parks needs a tribal recreation permit, and fishing the southern half needs a tribal fishing license.

Where should a group stay near Flathead Lake? In a whole home on the shore you plan to use most. The Tamarack is in Lakeside on the west side and The Evergreen is in Somers at the north end. Neither has private lake access.