Tickford Bridge in Newport Pagnell will be closed for essential repairs and maintenance works between July and November.
Milton Keynes Council will be carrying out repair and maintenance works on Tickford Bridge between July 4th to November 4th.
During this time period, the road will be closed to all traffic with a diversion route in place.
Due to the bridge being a Grade I Ancient Scheduled Monument, any works require months of planning and government approval.
Tickford Bridge, which goes over the River Ouzel in Newport Pagnell is one of the only cast iron bridges in Britain which still carries road traffic, it is also the oldest bridge in Milton Keynes - built in 1810.