The development of the political boundaries of the state of Missouri evolved over about a eighty year period of time, from about 1810 to 1890. During this span of time many boundaries were added, changed and changed again. A few were even broken up and ceased to exist. The earliest settled areas in Missouri were along the Mississippi and Missouri Rivers. The earliest settlements in these areas were by the French trappers and traders between 1710 and 1810. Many of these early French settlements still bear the French names and a number of developing counties were given their French names.

As Missouri was first beginning to be settled by English descendants under Spanish rule, between 1805 and 1819, the territory of Missouri was essentially five counties: 1) St. Charles, 2) St. Louis, 3) Ste. Genevieve, 4) Cape Girardeau, and 5) New Madrid. In the first territorial census in 1817, the pitiful few settlers in what is now Callaway County, Missouri, were enumerated in St. Charles County. If you will refer to the 'Census' page on this website you will find the St. Charles County census enumeration and what is now Callaway County is represented by Cote Sans Dessein Township. The French infulence at this point in time is most obvious when realizing that a very high percentage of the residents of the township are of French descent. Even after Missouri became a state in 1821 the county boundaries were continually being revised and a very large number of counties were added between 1821 and 1890.

Please note that when checking early census records for a county, it is wise to either check to see if there was a revision of county line or to determine whether the census of a particular county of interest was represented within the census of a neighboring county. If these efforts fail, it is wise to check the census records of adjoining counties.