Sumas Lake (Halq’eméyle: Semá:th Lake, Nooksack: Semáts Xácho7, (Level Place Lake)) was a shallow freshwater lake surrounded by extensive wetlands that once existed in eastern Fraser Lowland, located on the south side of the Sumas River between the foothills of Sumas Mountain (not to be confused with the same-named American mountain) and Vedder Mountain. It disappeared after being artificially drained for flood control and land reclamation from 1920 to 1924, leaving behind a low-lying flatland known as the Sumas Prairie, which is nowadays drained by the Saar Creek (a lower tributary of the Sumas River) and the namesaked Sumas Drainage Canal.