Both directions of Highway 401 will be closed Saturday night from Iona Road to Colonel Talbot Road.
The closure will take place from Saturday at 9 p.m. until Sunday at 9 a.m. while crews work on the demolition of the west half of the Union Road Underpass.
During the closure, Union Road will also be closed from Third Line to Fourth Line with no access to Highway 401.
Highway traffic will be rerouted via Iona Road, Talbot Line and Colonel Talbot Road with OPP assistance at intersections.