Waukegan police said officers were dispatched to a report of gunshots near Lincoln Avenue and 9th Street around 11 p.m.
There, officers found a man, believed to be in his late 40s to early 50s, who appeared to have suffered gunshot wounds. He was pronounced dead on the scene, and his name was not immediately released.
The Lake County Coroner's Office will determine the man's cause and manner of death and assist with confirming his identity.
What led up to the shooting was not immediately clear. Authorities did not immediately provide additional information.