Mercer County, NJ Special Events & Permits: Street Fair Rules (2026)

The Mercer County Park Commission's Rules and Regulations, adopted December 7, 2016, set the threshold for organized events under "Group Use, Meetings, Exhibitions": no group of fifty or more persons may use a county park or recreation area without first obtaining a group use permit no later than seven days before the proposed date of use. That permit requirement is what governs a festival, fair or vendor market big enough to draw a crowd, and adult supervision of any children's groups is required at all times during the event.

The rules single out open grove areas as the exception: those spaces are reserved for small family picnics of no more than 25 people, including children, and do not require a permit, but any group that wants a reserved area instead of open grove space must get one, and no alcohol permit will be issued for picnics in open grove areas regardless of size. Beyond the headcount permit, the same section bars holding a concert or public entertainment of any kind, or using loudspeakers, public address systems or amplifiers, anywhere in a county park without separate written permission obtained in advance from the Park Commission, meaning a street-fair-style event with a stage or PA system needs that additional sign-off on top of the group use permit.