It took roughly 40 firefighters from 10 area departments about an hour Sunday afternoon to bring the blaze under control.
A Waukegan police officer patrolling the beach noticed smoke rising around 3:34 p.m. in the grassy dunes area a mile north of the harbor, just east of the former Outboard Marine Corporation property.
Waukegan Fire called for mutual aid from area fire departments. Authorities evacuated swimmers in the beach area as firefighters fought to control the flames from spreading south. Firefighters were able to get a hose line south of the burning area to stop it from advancing.