The land where the Clear Lake Museum is located was platted in 1884 by E.S. Ellsworth of the Northwestern Land and Trust Co. The building was originally part of the Lockhart building, constructed in 1901 and leased to the post office from 1913 to 1933.
The Clear Lake Historical Society purchased the building in 1981. The early construction is still recognizable with the preservation of the block front. The intent of the museum is education into the history of the times and preservation of artifacts that relate to Clear Lake.
Since the Clear Lake centennial in 1984, the museum has made some improvements and additions. In 1987 the Lakeside District 18 schoolhouse was moved into town and placed behind the museum. In 2000 an addition was built onto the west end of the museum. The museum is open during special occasions such as Memorial Day, Rodeo Saturday, Dog Days, and also by appointment for tour groups, school groups, organizations and class and family reunions.