A few state demonyms are probably well-known. By demonyms we mean the words you call people or things from a specific state (like “Pennsylvanian”, “Texan” or the entertaining “Michigander”). But not everybody knows that state demonyms follow a regional pattern.
The regional patterns are revealed in this map from Twitter’s OnlMaps where you may find the demonyms recommended by the U.S. Government Publishing Office. It is obvious that states in the same region tend to have the same suffix in their demonym: the old South and the West Coast generally end an “-ian,” New England ends in “-er,” the West in “-an.” A few stray states use “-ite.”