Morris Plains elected a Democrat to replace longtime Republican mayor Frank Druetzler.
Jason Karr defeated Sal Cortese, the Republican, by 107 votes, 1,317 to 1,210.
Republicans held the two Morris Plains council seats.
Democrats picked up two seats on the Chatham Borough Council, with incumbents Leonard Resto (1,759) and Peter Hoffman (1,657) losing to Carolyn Dempsey (1,975) and Jocelyn Mathiasen (1,906).
In Madison, Democrats Astri Baillie (3,235) and Debra Coen (3,155) defeated Republican Kathy Dailey (2,735) and Mark Chiarolanza (2,665).
Republicans lead in a contest for three borough council seats in Mountain Lakes.
Just 17 votes separate Republican Matthew DeSantis (908) and Democrat Tom Menard (891).
The GOP held three council seats in Randolph.
