Motorists are warned the A57 in Crosspool, Sheffield, is to be closed from Friday, November 8, for three weeks while repairs are carried out following a landslide.
The busy road which links Sheffield with the Snake Pass, will be shut until Monday, December 2.
Traffic will be diverted along Rivelin Valley Road and Malin Bridge.
Graeme Symonds, network director at Amey which is carrying out the work as part of the Streets Ahead project, said: “Our technical experts carried out extensive investigations to identify the cause of the problem and discovered a collapsed drain in the hillside.
“Over time this has caused land movement in the area and, after measuring and monitoring this, we are now ready to start work to stabilise the embankment, install a new drain and repair the retaining wall.”
It is hoped the road will be fully reopened in January.