Osceola County is a county located in the U.S. state of Florida.Its county seat is Kissimmee. Osceola County was created in 1887. It was named for the Indian leader Osceola, whose name means "Singer of the Black Drink." Osceola County has a total area of approximately 1,506 square miles of which 88% is land and 12% water. As of the 2000 census, there were 172,493 people, 60,977 households, and 45,062 families residing in Osceola County, FL.