At least 40,000 people are expected to compete in the35th annual Shamrock Shuffle on Sunday.
The 8-K race starts and finishes in Grant park, and mirrors part of the Chicago Marathon route.
Sreets will close ahead of the 8:30 a.m. start time and will remain closed until about noon.
Parking restrictions along the course go into effect at 6 a.m.
Three main streets will remain open all day: Lake Shore Drive, Congress Parkway, and North Michigan Avenue.