District 15 is made up of 10 communities in Hunterdon and Mercer counties: East Amwell, Ewing, Hopewell Borough, Hopewell Township, Lambertville, Lawrence, Pennington, Trenton, West Amwell and West Windsor.
Voter registration is 40 percent Democrat and 13 percent Republican; most other district voters are unaffiliated.
The Democratic incumbents are facing one challenger for their party's nominations. Assemblyman Reed Gusciora, a Trenton resident and attorney elected to the Assembly in 1996, is running with Assemblywoman Elizabeth Maher Muoio of Pennington, who joined the lower house earlier this year. Dan Toto of Lawrenceville is seeking to unseat one of them.
Unopposed for the GOP nominations are Peter Mendonez Jr. of West Windsor and Anthony L. Giordano of Trenton.