The lift bridge in Placentia was closed to traffic around noon Sunday, after one end of the bridge collapsed and the lift side became stuck in the air.
Town officials said there is no word yet on what caused the collapse, but the bridge cannot be lowered to allow motor vehicle traffic to pass.
Crews with the town have been sent to asses the situation.
The town has made arrangements for a fire truck and an ambulance crew to be stationed on one side of the bridge.
There is no word yet on how long repairs to the bridge will take.