Round Lake (Bonner County, Idaho)

Round Lake is a 55 acre body of water located 4 mi southwest of Sagle in Bonner County, Idaho. It is the prime feature of Round Lake State Park and has 1.2 mi of shoreline. The maximum water depth is 34 ft. The lakeshore and watershed are heavily forested and undeveloped. The shoreline is undeveloped except for the public swimming beach at the state park.

Round Lake is eutrophic; its primary water source is Cocolalla Lake via Cocolalla Creek. The outflow is via the continuation of Cocolalla Creek. Most of the lake bottom is silt and detritus. Shore areas with a sandy bottom include the state park swimming beach.