The Fraser Lowland is a landform and physiographic region in the Pacific Northwest of North America, shared between the Canadian province of British Columbia and the U.S. state of Washington. The region includes much of the Lower Mainland region of British Columbia, and the coastal plains of Washington's Whatcom County. As a physiographic region, the Fraser Lowland is part of the Georgia Depression, which in turn is part of the Coastal Trough.
The eponymous Fraser River in the Lowland's north and the lower basins of its tributaries (mainly the Pitt River, Coquitlam River and Vedder/Chilliwack Rivers), as well as the entire catchment of the oppositely flowing Sumas River, are the Lowland's primary river system.