N.J. Stat. Ann. § 40:41A-104

The voters of any county shall have the power of initiative and, pursuant thereto, may propose any ordinance and may adopt or reject the same at the polls. Any initiated ordinance may be submitted to the board by a petition signed by a number of registered voters equal to 15% of the registered voters of the county as of 40 calendar days before the last most recent primary or general election.