Osceola County Government | 4,370 followers on LinkedIn. Proud to #befirsttowhatsnext, the nation’s 8th fastest growing county, and powered by more than 1,800 caring workers | Osceola County is a county rich in history and life. Created in 1887, Osceola County is a 1,506 square mile area that serves as the south/central boundary of the Central Florida greater metropolitan area. The city of Kissimmee, the county seat, is 18 miles due south of Orlando.