Spokane is the most populous city in and seat of government of Spokane County, Washington, United States. It is in eastern Washington, along the Spokane River, adjacent to the Selkirk Mountains, and west of the Rocky Mountain foothills, 92 miles (148 km) south of the Canadian border, 18 miles (30 km) west of the Washington–Idaho border, and 279 miles (449 km) east of Seattle, along Interstate 90.