Drivers who use St. Mary's Road to travel east-west through Green Oaks will need an alternate route on Tuesday, July 28. The Lake County Division of Transportation is closing the road for a full day to replace a deteriorated culvert beneath the pavement.
The closure spans St. Mary's Road between Illinois Route 137 (Buckley Road) and Illinois Route 176. Work begins at 8:30 a.m. Green Oaks sits immediately west of Lake Forest and Lake Bluff, and the affected stretch connects Route 176 traffic to Buckley Road, a corridor used by drivers heading to and from the Route 21 commercial area.
Detour and local access
The designated detour sends drivers from Route 137 to Route 21 (Milwaukee Avenue) to Route 176. Residents with homes along the affected stretch will still have limited access: local traffic is permitted from Route 137 south to King Drive and from Route 176 north to Lexington Road. The work site itself is closed to all traffic.
Why the closure
The Lake County Division of Transportation said the cross-road culvert has deteriorated and must be replaced to prevent flooding, erosion and pavement damage.
The project is one of roughly 30 in the division's $98 million 2026 construction program, announced Wednesday, April 8. The division said nearly half of that funding goes to preservation work on roads, bridges and drainage infrastructure.
What's next
Barring weather delays, St. Mary's Road should reopen by late afternoon Tuesday, July 28. Residents can sign up for real-time traffic alerts at lakecountypassage.com or through the LCDOT's GovDelivery notification page. Additional project details are available at lakecountyil.gov/transportation.
