The Rocky Mountain Trench is a huge glacial valley stretching 1500 km (930m), running unbroken from the Flathead Lake area of Montana to the Liard River in far northern British Columbia. It separates the Rocky Mountains on its east from the Columbia Mountains and the Cassiar Mountains on its west. It also skirts part of the McGregor Plateau area of the Nechako Plateau subarea of the Interior Plateau of British Columbia. It is up to 25km wide, peak-to-peak, and varies in depth, but is clearly visible from the air and disernible from high up on any of the mountain ridges lining it. A glaciated valley is one formed by the process of glaciation. ... Bathymetric Map of Flathead Lake Flathead Lake is the largest natural lake in Montana and the largest freshwater lake in the western United States. ... State nickname: Treasure State Official languages English Capital Helena Largest city Billings Governor Brian Schweitzer (D) Senators Max Baucus (D) Conrad Burns (R) Area  - Total  - % water Ranked 4th 381,156 km² 1 Population  - Total (2000)  - Density Ranked 44th 902,195 2. ... The Liard River is a river that flows through the Yukon Territory, British Columbia and the Northwest Territories, and in Canada. ... Motto: Splendor Sine Occasu (Latin: Splendour without diminishment) Official languages English Capital Victoria Largest city Vancouver Lieutenant-Governor of British Columbia Iona Campagnolo Premier Gordon Campbell (BC Liberal) Parliamentary representation  - House seat  - Senate seats 36 6 Area  - Total  - % water Ranked 5th 944,735 km² 2. ... White Goat Wilderness Area, Alberta, Canada The Rocky Mountains, often called the Rockies, are a broad mountain range in western North America. ... Columbia Mountains are in British Columbia, Canada, bounded by the Rocky Mountains in the east, and are made up of four large ranges: Cariboo Mountains, Monashee Mountains, Selkirk Mountains and Purcell Mountains. ... The Interior Plateau comprises a large region of central British Columbia, and lies between the Cariboo and Monashee Mountains on the east, and the Hazelton Mountains, Coast Mountains and Cascade Range on the west. ... Motto: Splendor Sine Occasu (Latin: Splendour without diminishment) Official languages English Capital Victoria Largest city Vancouver Lieutenant-Governor of British Columbia Iona Campagnolo Premier Gordon Campbell (BC Liberal) Parliamentary representation  - House seat  - Senate seats 36 6 Area  - Total  - % water Ranked 5th 944,735 km² 2. ...

It is used by four major river basins, the Columbia, Fraser, Peace and Liard's. Three reservoirs of the Columbia River Treaty fill much of its length today - Lake Koocanusa, Lake Kinbasket and Lake Williston. Rivers that use the trench are the Kootenay River, the Columbia River, Canoe River, Fraser River, Parsnip River, Finlay River, Fox River, and the Kechika River. The Kechika and Fox are part of the Liard system, the Parsnip and Finlay and part of the Peace River system. The Canoe River is a short tributary of the Columbia system, draining into Lake Kinbasket. The Kootenay River is a tributary of the Columbia, joining it near Trail B.C. after a quick trip through the United States as the Kootenai River. The Kootenai River, however, does not follow the trench but exists it southwest (as the Lake Koocanusa reservoir to the Libby Dam). The Fraser River is the longest river in British Columbia, Canada, rising in the Rocky Mountains near Mount Robson and flowing for 1400 km (870 mi), into the Pacific Ocean at the city of Vancouver. ... Peace River may refer to: The Peace River in Alaska in the United States, called by natives Gui-guok-lok The Peace River in Alaska in the United States, a tributary of the Koyuk River The Peace River in Florida in the United States The Peace River in British Columbia... The Liard River is a river that flows through the Yukon Territory, British Columbia and the Northwest Territories, and in Canada. ... The Columbia River Treaty is an agreement between Canada and the United States of America signed in 1961 and ratified in 1964 to develop the upper Columbia River basin with four large storage dams for hydroelectric power and flood control benefits in Canada and the U.S. The operation of... Lake Koocanusa is a reservoir in Montana and British Columbia Lake Koocanusa was named in a contest won by Alice Beers of Rexford, Montana. ... Williston Lake is actually a reservoir. ... The Kootenay River (spelled Kootenai River for its American portions) is the uppermost major tributary of the Columbia River, flowing through British Columbia, Montana and Idaho. ... Columbia River Gorge, Washington or North side The Columbia River is a river situated in British Columbia and the Pacific Northwest of the United States. ... The Fraser River is the longest river in British Columbia, Canada, rising in the Rocky Mountains near Mount Robson and flowing for 1400 km (870 mi), into the Pacific Ocean at the city of Vancouver. ... The Liard River is a river that flows through the Yukon Territory, British Columbia and the Northwest Territories, and in Canada. ... Peace River may refer to: The Peace River in Alaska in the United States, called by natives Gui-guok-lok The Peace River in Alaska in the United States, a tributary of the Koyuk River The Peace River in Florida in the United States The Peace River in British Columbia... Kinbasket Lake (or Kinbasket Reservoir) is a lake on the Columbia River, north of the town of Mica Creek and south of Golden. ... The Kootenay River (spelled Kootenai River for its American portions) is the uppermost major tributary of the Columbia River, flowing through British Columbia, Montana and Idaho. ... Trail as it appeared in 1908 Trail (49° 5′ 42″ N, 117° 42′ 36″ W) is a town in the Kootenay region of the interior of British Columbia, Canada. ... The Kootenay River (spelled Kootenai River for its American portions) is the uppermost major tributary of the Columbia River, flowing through British Columbia, Montana and Idaho. ... The Kootenay River (spelled Kootenai River for its American portions) is the uppermost major tributary of the Columbia River, flowing through British Columbia, Montana and Idaho. ... Lake Koocanusa is a reservoir in Montana and British Columbia Lake Koocanusa was named in a contest won by Alice Beers of Rexford, Montana. ... Libby Dam is a dam on the Kootenay River in Montana, United States. ...