Missouri is a state located in the Midwestern United States. In Missouri, cities are classified into three types: 3rd Class, 4th Class, and those under constitutional charters. A few older cities are incorporated under legislative charters (Carrollton, Chillicothe, LaGrange, Liberty, Miami, Missouri City, and Pleasant Hill) which are no longer allowed. (Carthage is also a Charter City and Charter Cities are by constitution not legislation and are still allowed to this day). The level at which they incorporate is determined by their population when they incorporate. They do not change if they gain or lose in population, unless a vote is held by the people.