Originally Posted by Wikipedia
The name Arkansas derives from the same root as the name for the state of Kansas. The Kansa tribe of Native Americans are closely associated with the Sioux tribes of the Great Plains. The word "Arkansas" itself is a French pronunciation ("Arcansas") of a Quapaw (a related "Kaw" tribe) word, akakaze, meaning "land of downriver people" or the Sioux word akakaze meaning "people of the south wind".
In 1881, the pronunciation of Arkansas with the final "s" being silent was made official by an act of the state legislature after a dispute arose between Arkansas's two U.S. senators as one favored the pronunciation as /ˈɑËrkÉ™nsÉ”Ë/ AR-kÉ™n-saw while the other favored /É‘ËrˈkænzÉ™s/ ar-KAN-zÉ™s.[c]