Ten days after settlers began to mark out claims of Wapello County, the first house was completed. In 1843 the Post Office was established. In May, 1844, Ottumwa was named the county seat. The first mill was built in 1845.

The beginning of industry in Ottumwa may be said to have been the mill, built at the foot of Market Street in 1845-6, by John Myers, David Armstrong and T. C. Coffin, on a tract of land containing three and one half acres, which was donated for the purpose by the Appanoose Rapids Company. In this old mill was manufactured much of the lumber that entered the early homes and business houses of Ottumwa, and here also was made flour and corn meal for the subsistence of the settlers.