Arizona • Joined United States: Feb. 14, 1912 (48th state to join) • Capital: Phoenix • Population: 7,123,898 It is not clear how Arizona got its name. Historian James H. McClintock believes ...

Louisiana’s name is much simpler than most of the state names on this list. The French named it after King Louis XIV, their monarch in the late 1600s and early 1700s.