The post of Mayor of the City of New Orleans () has been held by the following individuals since New Orleans came under American administration following the Louisiana Purchase â the 1803 acquisition by the U.S. of of the French province La Louisiane. In all mayoral elections since 1930, New Orleans has used a two-round system with a preliminary round and a runoff if no candidate reached a majority in the first round. All mayors of New Orleans since 1872 have been Democrats.