Kettle River Range Mountains, which in turn form part of the Columbia Mountains. The range runs north to south, bordered on the east by the Kettle River and the Columbia River, and on the west by the Kettle River, the Curlew Valley and the San Poil River. The mountainous region begins immediately north of the Canada–US border, at Grand Forks, British Columbia, extending 110 miles (177 km) south to the bend of the Columbia River and Lake Roosevelt, formed by Grand Coulee Dam, where it terminates. The Okanogan Highlands are adjacent to the range on the west, and the Selkirk Mountains are adjacent
Grand Coulee of Lower Grand Coulee. The Great Cataract forms the divide from the upper to lower coulees. The Lower Coulee tends along the monoclinal flexure to Soap Lake where the canyons end and the water flowed out into Quincy Basin. Quincy Basin is filled with the eroded gravels and silts from the Coulee. The Lower Coulee, also created its own path across the plains. Evidence of this is found in the tilted flows visible at Hogback islands in Lake Lenore and tilted flows along Washington 17 from Dry Falls to Park Lake. Numerous canyons acted as a distribution system for the