Spokane County is a county located in the U.S. state of Washington. As of the 2010 census the population was 471,221, making it the fourth-most populous county in Washington state. The largest city and county seat is Spokane, the second largest city in the state, behind Seattle.
Spokane County was formed on January 29, 1858. It was annexed by Stevens County on January 19, 1864, and re-created on October 30, 1879. It is named after the Spokane tribe.
According to the U.S. Census Bureau, the county has a total area of 1,781 square miles (4,610 km2), of which 1,764 square miles (4,570 km2) is land and 17 square miles (44 km2) (0.9%) is water. The lowest point in the county is the Spokane River behind Long Lake Dam (boundary of Stevens County) at 1538 feet (468 m) above sea level. (There is virtually no change in elevation between the dam and the mouth of the Little Spokane River inside Riverside State Park.) The highest point in the county is the summit of Mount Spokane at 5883 feet (1793 m).