Florida's 13th congressional district is an electoral district for the U.S. Congress on Florida's Gulf Coast, assigned to Pinellas County. The district includes Largo, Clearwater, and Palm Harbor. In the 2020 redistricting cycle, most of St. Petersburg facing Tampa Bay was redistricted into the 14th district, while the rest of Pinellas County formerly in the 12th district became included in the 13th district.

Pinellas County is a county located on the west central coast of the U.S. state of Florida. As of the 2020 census, the population was 959,107, which makes it the seventh-most populous county in the state. It is also the most densely populated county in Florida, with 3,491 residents per square mile. The county is part of the Tampa–St. Petersburg–Clearwater Metropolitan Statistical Area. Clearwater is the county seat. St. Petersburg is the largest city in the county, as well as the largest city in Florida that is not a county seat.