The heaviest flounder ever caught was 22 pounds, 7 ounces, landed in Montauk, N.Y., on Sept 15, 1975, by Charles Nappi. The species was a summer flounder, Platichthys flesus. This type of flounder ranges from South Carolina to Maine in the western Atlantic.

In August 2014, a fisher in New Jersey caught a flounder weighing 15 pounds, 3 ounces. Nine-year-old Ethan Wagner caught a state record 10.16-pound flounder in Galveston, Texas, in 2009.

The International Game Fish Association keeps official records of the largest fish ever caught, including 15 different species of flounder. Hundreds of game fish species are recorded in the IGFA's database.