Physical Characteristics. Orange County is in central Florida and is bordered by Seminole, Brevard, Osceola, and Lake counties. The county has 910.49 square miles of land and 93 square miles of water for a total of 1003.49 square miles. The average January temperature is 60.7 degrees fahrenheit, and the average August temperature is 82.0 degrees fahrenheit. The average annual rainfall is 52.35 inches.
History. Orange County was established in 1824 from a portion of St. Johns County. Originally named Mosquito, the county was renamed Orange in 1845 for the many orange groves in the area.