Borough voters approved a merger Tuesday by a margin of about 3-to-2. It was even more decisive in the township, where the change was supported by a margin of more than 5-to-1. The merger takes effect in 2013.
The township surrounds the borough like a doughnut, and Ivy League Princeton University straddles the town line.
Studies have shown taxpayers in both communities will save money by consolidating. But opponents have feared the change will cost the two towns their local identities.
New Jersey has 566 towns, many of them small.
The last time towns merged was in 1997 when Warren County's Hardwick absorbed Pohaquarry, population seven.
Borough resident Cole Crittenden, associate dean of undergraduate students at Princeton University, told The Times of Trenton that a merger will make things easier for the school.
"Trying to work with two governments causes a lot of confusion for the university and the students," he said. "For instance, the two towns' police departments have different policies for dealing with the students."
A nonprofit group that encourages municipal consolidation praised the vote, issuing a statement calling the Princetons trailblazers for their decision.
Courage to Connect New Jersey said it believes the decision will spur other consolidations around the state over the next few years. "More and more citizens are becoming empowered and recognize that they do, in fact, have a voice when it comes to streamlining and strengthening local government," the group said.
In 2007, state lawmakers created a commission to help the state determine which towns were ripe to merge or share services. The idea was to offer state funding to pay for transitional costs and lessen the burden on taxpayers if their taxes go up in the initial years, but the agency has sat largely dormant.
Gov. Chris Christie signed legislation in April making it easier for towns to form commissions that must approve putting merger plans on the ballot.