The victim is being treated at Carlisle’s Cumberland Infirmary.
An entire block of Senhouse Street was cordoned throughout yesterday, preventing businesses from opening.
Witnesses have described what happened as paramedics were called while townsfolk spoke of their shock.
Town clerk Lisa Douglas said she was only allowed into the town hall because she was able to provide a key for the litter bin outside.
“I understand the police were looking for a weapon.
“It was very sad, though. I could see blood on the pavement – a stark reminder of what had happened.”
The name of the victim has not been released by police.
However, locals believe he is a father of two young children.
One man was with the victim and other friends at the Labour Club.
“We shared a drink. He left and I followed. I saw him being attacked and ran back into the club to shout for help. When we came out he was lying on the ground.”
Robert Dowling was also in the Labour Club when the cry for help came.
He said he heard a woman scream.
People rushed to do what they could, he said.
Publican Moree Weir said the whole town was shocked by the incident.
“What is Maryport coming to?”
Police at the scene said the public had been understanding about the need to close off part of Senhouse Street, the town’s main shopping area.
Witnesses are being urged to call police on 101 or Crimestoppers - 0800 555 111.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here