Will County Sheriff's Department spokesman Ken Kaupas says the bodies of the two boys and two girls, aged 15 to 17, were recovered Tuesday from Forked Creek near the city of Wilmington.
Kaupas says the teens had been missing since Monday evening. Authorities don't know exactly when the accident occurred.
He says the driver likely lost control after hitting a patch of water or ice. The car tore through a guard rail and plunged into the water.
Wilmington School District Superintendent Jay Plese says the students' relatives have been notified but that names are being withheld out of respect.
Wilmington is 60 miles southwest of Chicago.