Revellers are believed to have smashed three windows at Chorley Town Hall.
People are thought to have punched windows on December 26 and January 5.
A bottle which had contained alcohol was thrown through a window on December 30.
Police are investigating and appealing for anyone who knows what happened to come forward.
They do not believe the three incidents are connected, but suspect people on nights out in the town centre could be responsible.
Call police on 101 or Crimestoppers on 0800 555 111 if you have information.