The Drefechan Bridge on the Pentre Llanrhaeadr to Llanynys road has been closed after damage caused by Storm Dennis.
Following an inspection, Denbighshire County Council has closed the bridge with immediate effect following high river levels over the weekend.
The Council is currently assessing the extent of the damage and will keep members of the public fully informed.
Diversions will be in place via Rhewl and the Council apologises for the inconvenience this will cause.
Cllr Brian Jones, the Council’s lead member for Waste, Transport and the Environment, said: “To ensure the safety of residents we have closed the bridge with immediate effect. We would like to thank members of the public for their understanding as we assess the full extent of the damage and we will ensure residents are kept informed.”