Why is there a Kansas City Kansas and a Kansas City Missouri?

In the United States, a city is a legal entity of a state (or territory or commonwealth, etc.). As such, it is impossible for the legal limits of a city to extend across state borders. This has led to cities which appear to cross borders, because they have the same name in both states, but which are actually separate cities, such as Kansas City (Missouri and Kansas) and Texarkana (Arkansas and Texas). The pairs share things like media outlets and civil organizations, but have separate governmental systems.

"Kansas City" in Missouri was originally settled by the French in the early 1800s, but soon was over run by a large population of Southerners and they called it "Possum Trot." The actually settlement became associated with the "Westport Landing," but in 1850 it was incorporated as the "Town of Kansas." The name was changed in the 1880s and the town was renamed "Kansas City." The name "Kansas" comes from its location at the edge the "Kansa," or Kaw, Indian territory, but mostly for its location at the confluence at the Kansas (Kaw) and Missouri Rivers.