Hosmer Lake is a natural body of water in the central Cascade Range in the U.S. state of Oregon.

[4] Hosmer Lake is about 5 miles (8 km) west of Mount Bachelor in Deschutes National Forest.

[1] The lake bottom consists of mud and peat, and mosses and aquatic plants restrict the open water.

[6] Formerly populated by trash fish, including carp, the lake was treated with rotenone in 1957 and restocked with Atlantic salmon.

Boats with electric motors may slowly ply the lake, which is also open to canoes and other non-motorized craft.