Peel Regional Police said they were summoned to a house in the Countryside Drive and Goreway Road area on Saturday night after learning that a house party was taking place inside, with cars parked throughout the yard and the surrounding area.
Officials said the owner or party organizer hired security to park the cars.
A neighbor told CP24 that other people were watching to make sure attendees were not filming the large gathering on their phones.
The organizer also erected barriers above the fence in the backyard of the house so that people could not see inside.
A video posted to social media showed numerous vehicles parked on the grass near the property.
Police said it took about an hour, until around midnight, to break up the party and send everyone home.
Under Ontario emergency rules, gatherings in Peel Region are limited to ten people, with physical distance between members of different households.
The parties have been blamed for dozens of recent COVID-19 infections in the Ottawa area.