There are 77 counties in the U.S. state of Oklahoma. Oklahoma is ranked 20th size and 17th in the number of counties, between Mississippi with 82 counties and Arkansas with 75 counties. Oklahoma originally had seven counties (Logan, Cleveland, Oklahoma, Canadian, Kingfisher, Payne, and Beaver) when it was first organized as the Oklahoma Territory. These counties were designated numerically, first through seventh. New counties added after this were designated by letters of the alphabet. The first seven counties were later renamed. The Oklahoma Constitutional Convention named all of the counties that were formed when Oklahoma entered statehood in 1907. Only two counties have been formed since then.