Hillsborough county (Florida) was established in 1834, and named after Lord Hillsborough, who was the British Colonial Secretary when the area was mapped by Dutch cartographer Bernard Romans in 1772. The county predates Florida's statehood, having been chartered in 1834. Orignially it covered most of southwest Florida, including modern-day Pinellas, Polk, Manatee, Sarasota, Charlotte, DeSoto, Hardee and Highlands counties, as well as parts of Lee county. Despite its huge area, the county's population at its inception was a whopping 836.

Today Hillsborough County is the fifth largest (by population) county in Florida with over 900,000 residents, and is home to the cities of Tampa, Temple Terrace, and Plant City.