Mercer County

East Windsor Township [1797: created through division of Windsor Township (1730)]
Ewing Township [1834]
Hamilton Township [1842]
Hightstown borough [1853]
Hopewell borough [1891]
Hopewell Township [1700]
Lawrence Township [1697: Maidenhead to 1816]
Pennington borough [1890]
Princeton borough [1813]
Princeton Township [1838]
TRENTON city [1792]- state capital/county courthouse
Washington Township [1860]
West Windsor Township [1797: created through division of Windsor Township (1730)]

Source:  New Jersey Localities: Civil Divisions and Municipalities; http://www.thegreenpapers.com/slg/localities.phtml?state=NJ