The Ministry of Transportation says Highway 17 will remain closed at least until Thursday morning east of Nipigon at the Jackfish River Bridge, 13 km east of Nipigon.
The road, which is part of the TransCanada Highway, was closed Tuesday "to facilitate emergency bridge repairs," according to a news release from the ministry.
During construction, "a structural deficiency" was discovered and that has "affected the structural integrity of the existing bridge", according to MTO spokesperson Annemarie Piscopo.
The Thursday re-opening is subject to an engineering review of the bridge.
No gas after 9 p.m. on detour
Drivers are being instructed to use Highway 11 and Highway 631 as an alternate route between Nipigon and White River.
It's a distance of more than 560 km.
The OPP is cautioning drivers who take the detour about the abundance of wildlife in the area and the shortage of gas stations.
"Fueling stations are few and far between in this area," an OPP news release said. "After 9:00 pm there is no fuel available between White River and Nipigon on Highway 631 and 11."