Police, fire and mountain rescue services are searching the River Eden, after reports a man jumped from Eden Bridge shortly before midnight last night.
The search is taking place from Eden Bridge towards Solway.
Passers-by saw a man, described as being in his 20s and wearing a dark hoodie and dark baseball cap, standing on the bridge.
They tried to engage him in conversation, however he jumped into the water.
Police and Fire and Rescue Services together with a police helicopter searched the area during the night and the search has resumed this morning.
Police would like to hear from anyone who may know the male and are appealing for people who may have seen him on the bridge last night.
Anyone with any information is asked to ring Cumbria Police on 101.