Hillsborough County is located in the west-central portion of the U.S. state of Florida. In the 2020 census, the population was 1,459,762, making it the fourth-most populous county in Florida and the most populous county outside the Miami metropolitan area. A 2021 estimate has the population of Hillsborough County at 1,512,070 people with a yearly growth rate of 1.34%, which itself is greater than the populations of 12 states according to their 2019 population estimates. Its county seat and largest city is Tampa. Hillsborough County is part of the Tampa–St. Petersburg–Clearwater Metropolitan Statistical Area.

Tampa is a city on the Gulf Coast of the U.S. state of Florida. The city's borders include the north shore of Tampa Bay and the east shore of Old Tampa Bay. Tampa is the largest city in the Tampa Bay area and the seat of Hillsborough County. With an estimated population of 398,173 in 2022, Tampa is the 49th-most populous city in the country and the third-most populous city in Florida after Jacksonville and Miami.