[3] Seminole County is part of the Orlando-Kissimmee-Sanford, Florida Metropolitan Statistical Area.

On July 21, 1821, two counties formed Florida: Escambia to the west and St. Johns to the east.

The name "Seminole" is thought to be derived from the Spanish word cimarron, meaning "wild" or "runaway".

As of the 2020 United States census, there were 470,856 people, 178,094 households, and 120,049 families residing in the county.

As of March 2009, according to Workforce Central Florida, the unemployment rate for Seminole County is 9.2 percent.

[19] The government operates under a County Charter adopted in 1989 and amended in November 1994.

Policymaking and the legislative authority are vested in the Board of County Commissioners, a five-member board elected to four-year terms in partisan, countywide elections and from single member districts.

The constitutional officers, clerk of the circuit and county courts, sheriff, tax collector, property appraiser, and supervisor of elections, maintain separate accounting records and budgets.

The board funds a portion or, in certain instances, all of the operating budgets of the county's constitutional officers.

The county provides a full range of services: the construction and maintenance of the county's infrastructure, public safety, recreation, health and human services, and development and protection of the physical and economic environment.

Republicans control all of Seminole County's partisan elected offices.

[23] There are five branches, located in the cities of Casselberry, Sanford, Lake Mary, Oviedo, and Longwood.