Round Lake State Park is a public recreation area located four miles (6.4 km) southwest of Sagle in Bonner County, Idaho. The 142-acre (57 ha) state park surrounds 123-acre (50 ha) Round Lake. The lake was formed from glacial activity in the Pleistocene. The park offers campsites, fishing, swimming, boating for non-motorized and electric-powered watercraft, and trails for hiking, biking and skiing.