JANESVILLE, chief town of Rock county, Wisconsin, U.S., was founded in 1836, and received its city charter in 1853. It contains numerous churches and schools, including the State institute for the blind. Rock river, flowing through the city, supplies water-power for five flour-mills, two woollen factories, and a cotton factory; and the manufactures comprise boots and shoes, carriages and farm machinery, and beer. The population in 1870 was 8789 ; in 1880, 9018.