The man identified as 23-year-old Joseph M. Mora of Oak Forest, authorities said Thursday.
Lockport Township Fire District Deputy Chief Frank Blaskey said responders were sent the 2500-block of Channel Road just after 1 p.m. Monday for a body in the water at the Lockport Locks, which connect to the Des Plaines River.
An autopsy was performed on Tuesday.
A final cause and manner of Mora's death has not been determined as toxicology reports are pending, authorities said.
Illinois State Police responded to the scene and was assisting with the investigation.
Authorities did not immediately provide further information.