WINNEBAGO, a new county in the N. part of Iowa, bordering on Minnesota, has an area of about 430 square miles. It is drained by the head waters of the Mankato and Tewapa Tankiyan rivers, tributaries of St. Peter's river. This county is not included in the census of 1850. County seat not located. (Baldwin's New and Complete Gazetteer of the United States..., 1854)
WINNEBAGO COUNTY Was organized in 1857, and is the central county in the northern tier. It is bounded on the east by Worth County, on the south by Hancock, and on the West by Kossuth, and contains 432 square miles, it being twenty-four miles east and west, and eighteen north and south. Line Creek runs in a southerly direction, through the eastern portion of the county....There is a large lake on the east side of the county.
FOREST CITY, the county seat, is situated on Lime Creek, in the south-eastern part of the county It contains one general store, blacksmiths, shoemakers' shops, etc. (Hair's Iowa State Gazetteer..., 1865)