The merger of the Borough and Township of Princeton marks the culmination of nearly fifty years of attempts to consolidate the two municipalities. The first serious effort to merge occurred in 1953, when 63% of township voters favored the initiative, but a majority of borough residents opposed it, highlighting the divide in local interests. Over the years, several subsequent attempts to unite were thwarted, primarily due to differing zoning requirements between the densely populated borough and the more spacious township.

In 1979, another consolidation effort gained traction, with 70% support from township voters; however, it ultimately failed in the borough by a mere 33 votes, a result upheld after a recount. A 1996 referendum saw township residents favoring a merger by nearly 3–1, but borough voters rejected the proposal, marking the sixth unsuccessful attempt.

The landscape shifted on November 8, 2011, when residents of both municipalities cast their votes on a merger proposal. This election was notably influenced by the participation of university students, who were encouraged to register and vote locally for the first time. This demographic shift likely played a significant role in the measure's success, as students, not homeowners, were less concerned about zoning issues. In the vote, 1,385 borough residents supported the merger compared to 902 opposed, while 3,542 township voters favored it against 604 who did not.

Proponents of the merger argued it would lead to significant savings of approximately $3.2 million through streamlined services, including potential layoffs of up to 15 government employees, including 9 police officers (though these layoffs were not mandated by the merger itself). On the other hand, opponents expressed skepticism regarding the reported cost savings, cited concerns over zoning discrepancies, and raised alarms about reduced voter representation in a smaller governmental structure.

The merger became effective on January 1, 2013, and marked a historic change, being the first municipal consolidation in New Jersey since 1997, when Pahaquarry Township merged with Hardwick Township. The unification of Princeton Borough and Township aims to enhance community services and create a more cohesive governance structure, setting a precedent for other municipalities facing similar challenges.