Mahaska County, Iowa
Founding: 1844 (declared in 1843) Parent counties: Keokuk and unorganized territory Namesake: Mahaska, Iowa chief Seat: Oskaloosa (1844–) Land area: 571 square miles Population (2020): 22,190 Population (historic): 5,989 (1850); 22,508 (1870); 28,805 (1890); 29,860 (1910); 25,804 (1930) Periods of population growth: pre-1850–1900; 1930s; 1970s; 1990–2010 Subdivisions: Ten cities; 18 townships Pre-1940 residences (estimated): 3,552 (36%) Pre-1940 housing survival rate: 44.8% Pre-1860 housing survival rate (1940): 8.8% Farm housing in disrepair (1950): 5.3% Nonfarm housing in disrepair (1950): 6.4% Average farmhouse value (1930): $2,139 Average outbuilding value (1930): $2,026 Average farmhouse size (1940): 6.4 rooms Number of farms (1920): 2,784 Average farm size (1920): 105.5 acres Sources of settlement: Ohio, Illinois, Pennsylvania, Indiana, New York, Missouri,...