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Flathead Lake

From Openwaterpedia
Emily von Jentzen doing a charity swim in Flathead Lake, Montana

Flathead Lake is the largest natural freshwater lake in the western part of the contiguous United States. With a surface area of about 191.5 sq mi (496 km2), it is slightly larger than Lake Tahoe. The lake is a remnant of the ancient inland sea, Lake Missoula of the era of the last interglacial.

Flathead Lake is 27.3 miles (43.9 km) long and up to 15.5 miles (24.9 km) wide with a maximum depth of 370.7 ft (113.0 meters), making it deeper than the average depths of the Yellow Sea or the Persian Gulf and about half the area of San Francisco Bay (main bay). The lake was raised 10 feet (3.0 meters) by Kerr Dam and is one of the cleanest in the populated world for its size and type.


Located in the northwest corner of the state of Montana, 7 miles (11 km) south of Kalispell, it is approximately 30 miles (50 km) long and 16 miles (25 km) wide, covering 191.5 square miles (495.9 km²). On the west side, the lake is flanked by U.S. Route 93, and on the east, by Route 35. The lake is bordered on its eastern shore by the Mission Mountains and on the west by the Salish Mountains.

Open Water Swimming[edit]

Length Crossings (25 miles)[edit]

Swimmer Name Date Time Details
1 Paul Stelter (Assisted) 20 Aug 1986 14:15 [1]
2 Ron Stevens (Assisted) 16 August 2005 12:25 [2]
3 Emily von Jentzen (Assisted) 17 July 2010 18:26 [3]

Vampire Swims[edit]

Flathead Lake is one of the global locations of the Vampire Swims, a series of open water swims held on 31 October.

Vampire Swims are also a great way to kick off the cold water, winter swimming season in those locations where swimming continues year round. Entry fee for these swims will include proof that the swimmer has donated blood within 6 weeks prior to the swim. Some venues are arranging a blood mobile to collect donations immediately after the swim. Those who cannot make a donation of blood for medical reasons can make a cash donation to the Red Cross or some other similar organization. A US$10 registration fee will also be expected of each swimmer to cover the cost of a custom, bloody-toothed swim cap and other incidental expenses with any remainder also to be donated to the Red Cross or other equivalent organizations that collect and distribute blood.


• Newport, Vermont (Lake Memphremagog) (Phil White)
• Boston, Massachusetts (Greg O’Connor)
• New York, New York (Jaimie Monahan)
• Westport, Connecticut (Liz Fey)
• Ottawa, Ontario (Nadine Bennett)
• Kingston, Ontario (Deborah Durbin)
Loch Ness, Scotland (Helen Beveridge)
Loch Lomond, Scotland (Chris Sifleet)
• Flathead Lake, Polson, Montana (Mark Johnston)

External links[edit]