A five-week programme of repairs is to begin on the B6161 in Harrogate.
Bridge work includes excavating the road to strengthen the arch as well as repairs to the parapet and surrounding walls.
Councillor Stanley Lumley, member for the Pateley Bridge division, said:
The scheme will be welcomed by commuters and residents as the road has become increasingly busier with those seeking alternative routes to the centre of Harrogate.
The repairs to this well-used bridge are part of our extensive programme to maintain and improve the county’s roads. We appreciate the closure will be an inconvenience to many however I would ask the public for their cooperation while the work is ongoing.
The repairs will begin on Monday, August 16, under a full road closure for the five-week duration.
During this time a diversion will be signposted via Beckwithshaw, Norwood and the A59.
Vehicles less than 7.5 tonnes can use nearby Oakdale Bridge. There will be a diversion in place for cyclists less than a mile away.