Piatt County, Illinois
Founding: 1841 Parent counties: DeWitt and Macon Namesake: James Piatt, local resident Seat: Monticello (1841–) Land area: 439 square miles Population (2020): 16,673 Population (historic): 1,606 (1850); 10,953 (1870); 17,062 (1890); 16,376 (1910); 15,588 (1930) Periods of population growth: pre-1850–1900; 1950–1980; 1990–2010 Subdivisions: One city; six villages; two CDPs; eight townships Pre-1940 residences (estimated): 1,950 (26.3%) Pre-1940 housing survival rate: 53.3% Pre-1860 housing survival rate (1940): 8% Farm housing in disrepair (1950): 4.2% Nonfarm housing in disrepair (1950): 6.3% Average farmhouse value (1930): $2,537 Average outbuilding value (1930): $3,060 Average farmhouse size (1940): 6.6 rooms Number of farms (1920): 1,386 Average farm size (1920): 182.5 acres Sources of settlement: Ohio, Indiana, and Pennsylvania ___________...