Florida's 21st congressional district is a U.S. congressional district on the Treasure Coast. In the 2020 redistricting cycle, the district was drawn as a successor to the previous 18th district and contains all of St. Lucie County and Martin County as well as the northeastern part of Palm Beach County, and includes Port St. Lucie, Fort Pierce, Stuart, Jupiter, and Palm Beach Gardens, as well as Treasure Coast International Airport. The previous iteration of the 21st district, which extended from Delray Beach to Palm Beach, was instead renamed the 22nd district.

Florida's 18th congressional district is an electoral district for the U.S. Congress, located in the Florida Heartland. In the 2020 redistricting cycle, the district was created as a new district, which includes the inland counties of DeSoto, Glades, Hardee, Hendry, Highlands, and Okeechobee, as well as most of Polk County and some of Immokalee in Collier County. The previous 18th district, located in the Treasure Coast, was instead renamed the 21st district.