Shuswap Lake (pronounced /ˈʃuːʃwɑːp/) is a lake located in south-central British Columbia, Canada that drains via the Little River into Little Shuswap Lake. Little Shuswap Lake is the source of the South Thompson River, a branch of the Thompson River, a tributary of the Fraser River. It is at the heart of a region known as the Shuswap Country or “the Shuswap”, noted for its recreational lakeshore communities including the city of Salmon Arm. The name “Shuswap” is derived from the Shuswap or Secwepemc First Nationspeople, the most northern of the Interior Salish peoples, whose territory includes the Shuswap.
Shuswap Lake consists of four arms, forming a shape reminiscent of the letter H. The four arms are called Salmon Arm (Southwest), Anstey Arm (Northeast), Seymour Arm (North), and the main lake (West). Shuswap Lake connects to Little Shuswap Lake via the Little River, which flows from the end of the west arm.
To the north-west it is fed by the Adams River, which drains Adams Lake. Shuswap Lake connects to Mara Lake at the Sicamous Channel. The Shuswap River connects via Mara Lake. In the south-west the Salmon River flows into the lake at Salmon Arm. TheEagle River runs down from the Eagle Pass in the Monashees to enter the lake at Sicamous, in the east. The Seymour Riverempties into the northern end of the Seymour Arm. In addition to these rivers, numerous creeks feed the lake, including Scotch Creek, which runs south to the north shore of the main arm, near the community of the same name.
The central interior plateau of British Columbia drained by the Fraser and Okanagan rivers is part of the Shuswap terrane in British Columbia and northern Washington state. It is dissected by numerous elongated, glacially-overdeepened lake basins which are formed by the same mechanisms as coastal fjords.