Hillsborough Area Regional Transit provides public transportation for Hillsborough County, Florida. The agency operates fixed-route local and express bus service, paratransit service, demand-response service, MetroRapid service, and the TECO Line Streetcar system. In 2023, the system had a ridership of 12,929,700.

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.