Area coe 850 is in use for the Florida Panhandle, USA. Area code 904 was used for the entire part of northern Florida from 11 July 1965, when 904 split from 305, until 904 itself was split in the mid-1990s. Permissive dialing for area code 850 began June 23, 1997 and mandatory dialing began March 23, 1998.