Vandals threw stones at staff at Astley Hall in Chorley who were trying to clean up a flood caused by the youths.
The gang of teenagers, believed to be aged around 13, caused major damage after they targeted Astley Hall and the Coach House, in Astley Park over the weekend of March 3-4.
Councillor Peter Wilson, deputy leader of Chorley Council, said: “The damage will likely run into thousands of pounds and it’s really disappointing to see people disrespecting all the work we are doing to make Astley Hall and park one of the top tourist attractions in the North West.
“We’d ask if anyone knows the people who did it to get in touch with us or contact the police on 101. We are reviewing CCTV footage and this will be handed to the police so we can identify the culprits.
“This mindless vandalism not only spoils it for everyone else but it is local council taxpayers who have to foot the bill and we’d rather be spending money on improving the Hall rather than having to put it towards repairs.”
According to the borough authority the four ran from room to room in Astley Hall dragging furniture around, damaging the newly restored flooring in the Townley Parker room, which had just been reopened.
They also kicked a radiator off the wall flooding the Coach House building. It means the activity space will be out of action while it is repaired. After that they targeted the lift and male toilets leaving graffiti.
Later in the day the group returned to taunt staff who were trying to sort the flood damage. They threw stones and used abusive language towards them.