Hillsborough County is a county in the U.S. state of Florida. In the 2010 census, the population was 1,229,226, making it the fourth most populous county in Florida. Its county seat and largest city is Tampa.Hillsborough County is part of the Tampa–St. Petersburg–Clearwater, FL Metropolitan Statistical Area.HistoryHillsborough County was created on January 25, 1834, from Alachua and Monroe counties, during the U.S. territorial period (1822–1845). The new county was named for Wills Hill, the Earl of Hillsborough, who served as British Secretary of State for the Colonies from 1768 to 1772. The County was created through efforts by Augustus Steele.The county's 1834 area was much larger and included eight other present-day counties: Charlotte County, DeSoto, Hardee, Manatee, Pasco, Pinellas, Polk, and Sarasota.
