Princeton Township was a township in Mercer County, in the U.S. state of New Jersey, that existed from 1838 until the end of 2012. On January 1, 2013, it merged with the Borough of Princeton to form Princeton, New Jersey; both Princeton Township and the Borough of Princeton were dissolved in the merger.
As of the 2010 United States census, the township's population was 16,265,
Princeton was incorporated as a township by an act of the New Jersey Legislature on April 9, 1838, from portions of West Windsor Township in Mercer County and Montgomery Township in Somerset County. The Borough of Princeton — created on February 11, 1813 within the area that later became Princeton Township — became a fully independent municipality circa 1894. Portions of territory were ceded to the Borough of Princeton on January 4, 1928 and August 21, 1951. On November 8, 2011, voters in Princeton Township voted to consolidate with Princeton Borough, a change that took effect on January 1, 2013.
The Institute for Advanced Study, a private research institution that has been an academic home to Albert Einstein, Kurt Gödel, and many other famous and prize-winning scientists, is located in the former township. Princeton University is located mostly within the former borough, but parts of the campus extended into what was Princeton Township.
Drumthwacket, the official residence of the governor of New Jersey, is located at 344 Stockton Street in the area of the former township.
The last day Princeton Township existed as an independent municipality was December 31, 2012.
Geography
According to the United States Census Bureau, the township had a total area of 16.520 square miles (42.786 km<sup>2</sup>), including 16.090 square miles (41.672 km<sup>2</sup>) of it is land and 0.430 square miles (1.114 km<sup>2</sup>) of water (2.60%) is water.
Princeton Borough was an independent municipality completely surrounded by the township.
Princeton North was an unincorporated community located within Princeton Township that had been a census-designated place until the 2010 census.
The Princeton Airport is within Princeton's postal district but is situated less than a mile across the Somerset County border, in Montgomery Township.