Peel Region police say the officers who arrived at the so-called "mansion party" northwest of Toronto Friday night quickly realized backup was needed.
Const. Thomas Ruttan says several arrests were made after officers were allegedly assaulted. He says some partiers were also picked up for public intoxication but no injuries have been reported.
Police say the Twitter-promoted event caused an estimated $70,000 in damage to the home, which is undergoing renovations.
They say the party organizer had permission to host the party but did not expect so many people to attend.
Police say the homeowner and neighbours called police when noise and traffic got out of hand, but the owner isn't likely to face charges.