Physical Characteristics. Okaloosa County is in northwest Florida and is bordered on the north by Alabama, on the south by the Gulf of Mexico, on the east by Walton County, and on the west by Santa Rosa County. The county has 935.81 square miles of land and 59.57 square miles of water for a total of 995.38 square miles. The average January temperature is 51.4 degrees fahrenheit. The average August temperature is 80.3 degrees fahrenheit. The average annual rainfall is 63.70 inches.
History. Okaloosa County was established in 1915 from portions of Santa Rosa and Walton counties. Okaloosa is possibly derived from Choctaw aka meaning "water" and lusa meaning "black". The combination of these two words may refer to the Blackwater River in Okaloosa County.
