The borough was located in Mercer County, in the U.S. state of New Jersey, and was completely surrounded by the former Princeton Township, from which it was formed in 1894.

[17] The Borough of Princeton was incorporated by an act of the New Jersey Legislature on February 11, 1813, within portions of West Windsor Township (in what was then part of Middlesex County) and Montgomery Township (in Somerset County), and was reincorporated on November 27, 1822.

The borough became part of the newly created Mercer County in 1838, and became a fully independent municipality circa 1894.

Portions of territory were acquired from Princeton Township on January 4, 1928, and August 21, 1951.

According to the U.S. Census Bureau, the borough had a total area of 1.843 square miles (4.774 km2), all of which was land.

[7][20] The 2010 United States census counted 12,307 people, 3,161 households, and 1,644 families in the borough.

[28] As of the 2000 United States Census[14] there were 14,203 people, 3,326 households, and 1,692 families residing in the borough.

[27][29] The borough's unusually low median age and high concentration of 18- to 24-year-olds is influenced by Princeton University.

The mayor of the Borough of Princeton, New Jersey, was Yina Moore (D, term ended on December 31, 2012).

Members of the borough council were Jo Butler (D, 2012), Jenny Crumiller (D, 2012), Heather Howard (D, 2012), Roger Martindell (D, 2012), Barbara Trelstad (D, 2012) and Kevin Wilkes (D, 2012).

Proponents of the merger asserted that when the merger is completed the new municipality of Princeton will save $3.2 million as a result of some scaled-down services, including layoffs of 15 government workers, including 9 police officers (however, the measure itself does not mandate such layoffs).

Opponents of the measure challenged the findings of the report, citing cost savings as unsubstantiated, and noted that voter representation would be reduced in a smaller government structure.

[10][35] Prior to the 2011 reapportionment following the 2010 Census, Princeton Boro had been in the 15th state legislative district.

However, the university owns more land in West Windsor than in the two Princeton municipalities combined.

Westminster Choir College (part of Rider University) and most of Princeton Theological Seminary were located in the borough.

Princeton is the setting for the fictional Princeton-Plainsboro Teaching Hospital in the TV series House.