Flathead Lake, Montana, USA

Lake Locations:

USA - West - Montana - Glacier Country -

Carved out by the historic glaciers of the last ice age approximately 11,000 years ago, Flathead Lake is one of the largest natural freshwater lakes in the western United States. The Kerr Dam regulates water flow from the lake’s major tributaries — the Flathead and Swan Rivers — providing hydroelectric power, water for irrigation, and flood control. Nestled in the heart of the 100-mile long Flathead Valley in northwest Montana, this moraine-dammed lake has a surface area of 122,500 acres. Its 161-mile shoreline outlines vast hiking trails of majestic mountain ranges, making it a one-stop destination for all water and land sport enthusiasts.

The glittering blue water of Flathead Lake takes its name from its earliest settlers — the Bitterroot Salish (Flathead), Kootenai and Pend d’ Orielles tribes — residing at the Flathead Indian Reservation located at the southern half of the lake. The Mission Mountain Range towers its eastern shore, and the Salish Mountain Range, the west. The exotic Bob Marshall Wilderness is a backdrop of visual delight.

Kerr Dam, owned by PPL Montana, is jointly operated with the Confederated Salish and Kootenai Tribes of the Flathead Indian Nation. The dam went into operation in 1938, raising the level of Flathead Lake by 10 feet over its natural outlet. Water levels are maintained between 2,283 and 2,293 feet above sea level. The expansive lake stretches almost 28 miles long and 16 miles wide at its widest point.

Packing your bags for a leisure or adventure tour of Flathead Lake brings you to its beautifully landscaped vacation and residential areas with first class amenities. Whether you are a couple who wants a get-away in a private harbor, or an entire family that wants to join fun-filled communities in and around the cities or State Parks, Flathead Lake has it all.

Anglers find rich fishing waters at Flathead Lake. It is an aquatic habitat to 25 fish species including the yellow perch, lake trout, lake whitefish, pearmouth minnow, largescale sucker, and sculpin. But the finest game fishes are the cutthroat, mackinaw, kokonee and the trophy-size bull trout. Ice fishing is popular during the winter.

As an added amusement, Flathead Lake is also home to the fabled Flathead Lake monster known as Flathead Nessie. Nessie has been described as a whale-shaped or eel-shaped creature about 20 to 40 feet long, with piercing ebony eyes. Sightings have been recorded over the past hundred years, but no actual photos are available.

Many watercraft, propelled by paddle, motor, and sail, traverse the waters of Flathead Lake. You can play in, on or by the water, without worrying about crowding. White-water rafting, water skiing, wakeboarding, tubing, diving, parasailing and hydrobiking are famous water sports here. The sheer size of the lake can accommodate anyone, everyone, anytime. You can bring your own water toys or rent them from nearby marinas. Or, sitting by the shore with the waves lapping at your feet is also not a bad idea.

The area that surrounds Flathead Lake is as massive and wonderful as the lake itself, making it the adventurer’s ultimate paradise. Though it has no central hub for visitors, Flathead Lake State Park offers six different units: Wild Horse Island, Big Arm, Finley Point, Wayfarers, West Shore, and Yellow Bay. Each park provides its own unique recreation and wildlife viewing. The 2,100-acre Wild Horse Island is the largest among the parks. It is a popular camping site for hikers, mountain climbers and RV owners. You can even saddle up for a relaxing horse ride along homesteads and larch-lined trails, and get an occasional glimpse of deer, Bighorn sheep and grizzly bears. To add color to your cheeks, a nice sunbath at the Big Arm unit’s pebble beach is delightful. Boaters, swimmers and campers can also indulge in the breathtaking views and secluded privacy of West Shore Park, enjoying the fresh scent of tall firs and pines. Pick wildflowers and commune with park residents at Wayfarers by setting-up a picnic table. This area provides boat ramps, trailer dumps and dock fishing zones. If you plan your trip on time, you may even get a taste of delectable cherries from the orchards within Yellow Bay area. Scuba divers and swimmers frequent the bay as it is the deepest area of Flathead Lake’s waters. At the lake’s southeast end is the Finley Point unit with campsites, running water, boat slips and pump-out stations.

The full range of visitor services extend to Glacier National Park, 30 miles north of Flathead Lake, offering a spectacular view of valleys, ridges, peaks and wildlife. Other golden attractions are the Ninepipe National Wildlife Refuge which is sanctuary to over 200 species of birds, and of course, Flathead Valley which was named by Golf Digest as one of the Top 50 Golf Destinations. Needless to say, golf is also a very popular sport among residents and vacationers at Flathead Lake.

Concerts and festivals are celebrated in the charming and historic towns and cities of Kalispell, Polson, Big Fork, Somers and Elmo. Take part or watch the annual Flathead Lake Hoopfest, Cherry Blossom Festival and Full Moon Cruise. These are just some of the many much awaited events.

No place can top the natural beauty, splendor and experience that Flathead Lake offers. So, whether you want to sweat or get wet, the “Jewel of the Northwest” awaits you to enjoy its collection of marvelous state park units and cool, pristine waters. Come and don’t delay any longer. The lake monster sure is waiting to pose for a snapshot from you!

Things to do at Flathead Lake

  • Vacation Rentals
  • Fishing
  • Ice Fishing
  • Boating
  • Sailing
  • Swimming
  • Beach
  • Water Skiing
  • Wakeboarding
  • Parasailing
  • Tubing
  • Scuba Diving
  • Golf
  • Camping
  • Picnicking
  • Hiking
  • Mountain Climbing
  • Horseback Riding
  • Wildlife Viewing
  • Birding
  • National Wildlife Refuge
  • State Park
  • National Park

Fish species found at Flathead Lake

  • Bull Trout
  • Eel
  • Lake Trout
  • Perch
  • Sculpin
  • Sucker
  • Trout
  • Whitefish
  • Yellow Perch

Flathead Lake Photo Gallery

Flathead Lake Statistics & Helpful Links

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Lake Type: Natural Freshwater Lake, Dammed

Water Level Control: PPL Montana

Surface Area: 122,560 acres

Shoreline Length: 161 miles

Normal Elevation (Full Pond): 2,893 feet

Average Depth: 165 feet

Maximum Depth: 371 feet

Water Volume: 1,200,000 acre-feet

Water Residence Time: 3.4 years

Drainage Area: 7,086 sq. miles

Trophic State: Oligomesotrophic

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Trophic State | LakeLubbers

Trophic State measures the level of algae and nutrients in a lake.

An oligotrophic lake is very clear (blue in color) and does not support much plant or fish life. A hyper-oligotrophic lake is the clearest of all lakes, and is nearly devoid of plants and fish.

A mesotrophic lake is slightly green and supports a moderate degree of plant and fish life. A lake's most desired trophic state is generally this mid-point - the mesotrophic state.

A eutrophic lake is somewhat murky and supports a large amount of plant and fish life. A hypereutrophic lake is clouded with algae, plant life, and fish life. A eutrophic or hyper-eutrophic lake can be difficult to navigate by boat - and is often an unpleasant place to swim.

The use of phosphorus-rich and nitrogen-rich fertilizer on lawns and golf courses surrounding a lake can cause it to become eutrophic or hypereutrophic.


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Catchment or Drainage Area | LakeLubbers

This is the surrounding area that drains into a lake, including land, rivers and their tributaries. This is also known as the lake's "catchment basin".

Small lakes at the highest peaks of mountains have small drainage areas. The world's oceans have the largest drainage areas.


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Lake-Area Population | LakeLubbers

This is the estimated number of people who live in a house with a view of a lake, plus those who self-describe the lake as their home, for example: "I live at Smith Mountain Lake."


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Water Residence Time | LakeLubbers

This is the estimated time that it takes for an amount of water equal to the entire volume of a lake to flow out of - or evaporate from - the lake.

Residence Time can be as short as a few days for fast-flowing small lakes, and can exceed 100 years for slow-flowing large lakes.


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Completion Year | LakeLubbers

This is the year that a reservoir was first filled to the reservoir's normal elevation - or the year that a natural lake was first dammed. A large reservoir can take more than a year to fill after its dam is first closed.

The Grand Anicut in southern India is generally considered the world's oldest dam that still operates. Grand Anicut was constructed in the second century BC. It now impounds an irrigation network that includes roughly one million acres.

You can find many of the the world's newest reservoirs on LakeLubbers. Many of the world's oldest reservoirs appear on the last page of that list.


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Water Volume | LakeLubbers

This is the estimated volume of water that a lake contains -- measured at the lake's normal elevation. By this measure, the world's largest freshwater lake is Siberia's Lake Baikal.

You can find many of the the world's largest lakes (by water volume) on LakeLubbers.

Water Volume can be measured in acre-feet, in cubic miles, or in cubic kilometers. One acre-foot is the amount of water needed to cover one acre (43,560 square feet) to a depth of one foot. One cubic mile equals 3,379,200 acre-feet. One cubic kilometer equals 810,713 acre-feet.

1 acre-foot is equal to 325,851 US gallons. Siberia's Lake Baikal contains about 6,276,367,740,000,000 gallons of freshwater - nearly 1 million gallons for every living person on earth.

The other - and more widely used - measure of a lake's size is the lake's surface acreage. By that measure, the world's largest freshwater lake is North America's Lake Superior.


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Maximum Depth | LakeLubbers

This is the estimated greatest depth of the water in a lake -- measured at the lake's normal elevation. The world's deepest lake is Siberia's Lake Baikal; that lake's maximum depth is estimated at 5,314 feet.

You can find many of the the world's deepest lakes on LakeLubbers. If you select the last page of that list, you will find the (maximum depth of) the shallowest lakes in our database.


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Average Depth | LakeLubbers

This is the estimated average depth of the water in a lake -- measured at the lake's normal elevation. If the water volume and surface area of a lake are known, an estimate of the lake's average depth can be calculated:

Water volume ÷ Surface Area = Average Depth

Example: 1,000,000 acre-feet ÷ 20,000 acres = 50 feet average depth


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Maximum Elevation | LakeLubbers

This is a lake's highest water level, measured by the lake's surface distance above sea level, that can occur during flooding. A lake's highest possible maximum elevation is usually the top of the lake's dam or spillway.

At lakes that include residential development, government regulations usually forbid the construction of homes below a lake's maximum elevation.


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Minimum Elevation | LakeLubbers

This is a lake's lowest water level, measured by the lake's surface distance above sea level, that can be reasonably expected to occur. Low lake levels can occur due to deliberate seasonal draw downs for irrigation or impending snow melt, reduced water inflows, drought and evaporation, residential or commercial water demands, and hydropower generation.

Some lakes' minimum and maximum elevations are virtually the same. Lakes that generate hydropower may vary by several feet - according to power demand. Lakes whose primary purpose is to prevent flooding can seasonally vary by 100 feet or more.

When some lakes reach their minimum elevation, their boat ramps may not be long enough to permit boat access - and boats docked on shallow parts of the lake may end up on dry ground. In those cases, kayakers and shore-based anglers may be among the few happy recreational users of the lake.


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Normal Elevation | LakeLubbers

This is a lake's normal water level, measured by the lake's surface distance above sea level. For a reservoir, this water level is also known as "full pond" or "full pool".

You can find many of the world's highest-elevated lakes on LakeLubbers. Lakes with the lowest elevations (known by LakeLubbers) are shown on the final page of that list.


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Shoreline Length | LakeLubbers

This is the length of the exterior shoreline around a lake - measured at the lake's normal elevation. The shoreline length can be considerably shorter or longer when lake water levels are lower or higher than normal.

A lake with many coves has a much longer shoreline than a lake of similar surface area that is nearly circular in shape.

When known, the shoreline miles that we report in our statistics include only the lake's exterior shoreline, and exclude the shorelines of islands located within a lake's boundaries. In lakes with many islands, those islands' combined shorelines may exceed a lake's exterior shoreline.

You can find many of the world's longest-shoreline lakes on Lakelubbers.


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Surface Area | LakeLubbers

This is the area (acreage, square kilometers, etc.) of the top surface area of a lake - measured at a lake's normal elevation. The surface area can be considerably smaller or larger when lake levels are lower or higher than normal. North America's Lake Superior is the world's largest freshwater lake by this measure.

The other measure of a lake's size is the lake's water volume. By that measure, the world's largest freshwater lake is Lake Baikal in Siberia.

You can find many of the world's largest lakes (acres) on Lakelubbers. There is no widely-accepted minimum surface area that defines a lake. What Lakelubbers describes as a lake, you might call a pond. The smallest lake that Lakelubbers currently includes is Hawaii's 2-acre Lake Waiau.


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Water Level Control | LakeLubbers

This is the organization that controls water releases or outflows from the lake or reservoir. In the USA, this is often the US Army Corps of Engineers, a power company, a municipal water system, an irrigation district, or a paper manufacturing company. In the case of private or gated lakes, a homeowners' association may be the lake's controlling authority.

Many lakes cross borders, including North America's Great Lakes. The control of such lakes and their coveted freshwater may be amicably shared - or hotly disputed.

"Water wars" continue at many lakes as growing populations and crop irrigation needs compete for the freshwater that lakes contain.


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Lake Type | LakeLubbers

There are 3 basic types of lakes that are currently included on LakeLubbers. 2 types may be dammed or not dammed, producing 5 classifications.

- A Reservoir is a man-made freshwater lake that is usually created by damming rivers.

- A Natural Freshwater Lake occurs naturally - often by glacial activity - and has a salinity of less than 30 parts per thousand. It may be dammed to produce electricity or for other reasons.

- A Natural Saltwater Lake occurs naturally and has a salinity of more than 30 parts per thousand (ppt). It may be dammed.

"Brackish" water may be categorized as freshwater or saltwater, depending on its salt content (salinity). Oligohaline water has less than 15 ppt of salt. Mesohaline water has 15-29 ppt. Polyhaline has 30-335 ppt.


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