Hillsborough County is a county in the U.S. state of Florida. In the 2010 census, the population was 1,229,226,[2] making it the fourth-most populous county in Florida and the most populous county outside the Miami Metropolitan Area. A 2017 estimate has the population of Hillsborough County at 1,408,566 people,[3] which itself is greater than the populations of 10 states[importance?] according to their 2017 population estimates.[4] Its county seat and largest city is Tampa.