Physical Characteristics. Manatee County is bordered by Hillsborough, Hardee, De Soto, and Sarasota counties. Anna Maria Key and a portion of Longboat Key separate the mainland from the Gulf of Mexico. The county has 747.13 square miles of land and 52.25 square miles of water for a total of 799.38 square miles. The average January temperature is 61.5 degrees fahrenheit, and the average August temperature is 81.2 degrees fahrenheit. The average annual rainfall is 54.60 inches.
History. Manatee County was established in 1855 from portions of Hillsborough and Mosquito counties. The county was named for the manatee (also know as the sea cow), an endangered species found in its waters. According to some accounts, Hernando de Soto landed on Terra Ceia Island and began his trek north from present-day Manatee County.
