Highland Park Mayor Gayle Brill Mittler defeated her Democratic primary challenger, Monique Coleman, by a 59%-41% margin.
Mittler, the mayor since 2014, won by 363 votes, 1,239 to 876.
In the race for borough council, incumbents Philip George and Matthew Hale defeated M. Austin Morreale by a wide margin.
Hale was the top vote-getter with 1,429 votes, followed by George at 1,283. Morreale received 885 votes.
The Democratic nomination is tantamount to election in heavily Democratic Highland Park. The last Republican to win was Jeff Orbach, who won an upset victory in the 1991 anti-Jim Florio Republican wave and served just one term.