Osceola County was created in 1887. On July 21, 1821, Florida was divided into two counties, named Escambia County to the west and St. John's County to the east. In 1824, the southern part of St. John's County became Mosquito County, with Enterprise as the county seat. In 1844, Brevard County was carved out from Mosquito County. When Florida became a state in 1845, Mosquito County was renamed Orange County. On May 12, 1887, Osceola was named a county, having been created from both Orange and Brevard Counties. Osceola County reached all the way down to Lake Okeechobee until 1917 when Okeechobee County was formed.

Since the late 20th century, Osceola County has experienced a significant influx of migrants from the Commonwealth of Puerto Rico, the unincorporated territory of the United States, and in the 2000 U.S. Census Puerto Rican was the largest self-reported ancestry group.

Osceola County is a charter county, and a subdivision within the State of Florida. Voters approved the County Charter in March 1992, and it took effect on October 1, 1992. The structure of County government under the charter does not depart dramatically from the structure of a County government outlined in the Florida Statutes.

--Wikipedia

Surrounding counties:

Brevard | Highlands | Indian River | Lake | Okeechobee | Orange | Polk