Police blocked King Street, Clitheroe, after a police officer appeared at a top-floor window of the police station and refused to come down.
The incident happened at around 1am on Monday and the stand-off lasted several hours while colleagues attempted to persuade the officer to come down.
A passer-by who was out walking his dog said: “He was at the top window shouting about a grievance he had and he wouldn’t come down until it was sorted out.
“I could see five or six officers outside the police station, and the police were stopping people going into the street.”
A county police spokesman said: “Police were called shortly before 1am on Monday after concerns were raised about the welfare of a man inside a building on King Street.
“Officers attended and spoke to the man, who voluntarily came out of the building some time later. He was unharmed and is now being offered suitable support.
“King Street was closed for a time while the incident was dealt with.”