Lancaster Road, in Morecambe, will be closed for up to a month whilst repair work takes place.
The section of road from Branksome Drive to South Avenue will be closed for major reconstruction work.
A diversion will be signed from Lancaster Road, Broadway, Marine Road East, Lord Street, Euston Road, Lancaster Road, and vice versa. The closure is from July 25 to 26 August.
Dan Chalmers, Lancashire County Council highways manager for Lancaster, said: “This section of Lancaster Road is in a bad condition and we need to fully reconstruct it.
“This is a big job on a busy section of road, but it is much-needed and will provide a good quality new surface which should last for many years.
“We’ll do all we reasonably can to minimise disruption, and will ensure people can still access the Sainsbury’s store at all times. As we don’t need to resurface the junction leading to the store, the scheme will be completed in two sections to allow access to the store to be maintained.”