Sister cities of Princeton, New Jersey

Princeton is a municipality with a borough form of government in Mercer County, New Jersey, United States, that was established on January 1, 2013, through the consolidation of the Borough of Princeton and Princeton Township. As of the 2010 United States Census, the borough's population was 28,572, reflecting the former township's population of 16,265, along with the 12,307 in the former borough.

Princeton is best known as the location of Princeton University, which has been sited in the community since 1756. Although Princeton is a "college town", there are other important institutions in the area, including the Institute for Advanced Study, Westminster Choir College, Princeton Theological Seminary, Educational Testing Service (ETS), Opinion Research Corporation, Siemens Corporate Research, Bristol-Myers Squibb, Sarnoff Corporation, FMC Corporation, The Robert Wood Johnson Foundation, Amrep, Church and Dwight, Berlitz International, and Dow Jones & Company.

Princeton is roughly equidistant from New York City and Philadelphia. Princeton is close to many major highways that serve both cities, and receives all major TV and radio broadcasts from each.

New Jersey's capital is the city of Trenton, but the governor's official residence has been in Princeton since 1945, when Morven in the borough became the first Governor's mansion. It was later replaced by the larger Drumthwacket, a colonial mansion located in the township. Morven became a museum property of the New Jersey Historical Society.

Princeton was named No. 15 of the top 100 towns in the United States to Live and Work In by Money Magazine in 2005.

Although residents of Princeton (Princetonians) traditionally have a strong community-wide identity, the community had been composed of two separate municipalities: a township and a borough. The central borough was completely surrounded by the township. The Borough seceded from the Township in 1894 in a dispute over school taxes; the two municipalities later formed the Princeton Public Schools, and some other public services were conducted together before they were reunited into a single Princeton in January 2013. The Borough contained Nassau Street, the main commercial street, most of the University campus, and incorporated most of the urban area until the postwar suburbanization. Borough and Township had roughly equal populations.

United States Postal ZIP codes for Princeton include 08542 (largely the old Borough), 08544 (the University), 08543 (the Seminary), and 08540. The latter covers areas outside Princeton proper, including portions of Lawrence, Hopewell, and West Windsor Townships in Mercer County, Montgomery and Franklin Townships in Somerset County, and Plainsboro and South Brunswick Townships in Middlesex County.