Forms to register in New Jersey's June 7 primary are available at municipal offices, county election offices and online at the state Division of Elections.
Tuesday is the registration deadline to participate in the primary, which includes selecting the candidates who will run for president in November.
Voters in New Jersey can only select candidates for the party in which they are registered.
As of the end of April, more than 5.5 million New Jerseyans were registered to vote. Of those, 1,771,461 were Democrats and 1,077,360 were Republicans. Some 2,652,061 were not affiliated with any political party.
Unaffiliated voters must declare a party affiliation in order to participate in the primary. They can do that at the polling place during the primary.