A key crossing on the River Thames will be closed to traffic for 20 weeks for essential maintenance.
Cookham Bridge, which links Cookham in Berkshire with Bourne End in Buckinghamshire, is closed to vehicles but will remain open for pedestrians.
The work aims to extend the life of the 183-year-old, Grade II listed, iron structure.
During the closure, motorists face diversions of up to 16 miles. Businesses will remain open as usual.
Concerns were previously raised about the effect of the closure on hospitality businesses, particularly over the Christmas period.
But Royal Borough of Windsor and Maidenhead said the "six months of pain" would mean decades of easy operation of the bridge.
The work includes re-painting of steelwork, structural bearing replacement, structural strengthening, re-waterproofing and re-surfacing.