According to the United States Census Bureau, the city had a total area of 6.034 square miles (15.626 km2), including 6.023 square miles (15.599 km2) of land and 0.011 square miles (0.027 km2) of water (0.18%) [REF].
Plainfield is in the Raritan Valley, a line of cities in central New Jersey, and lies on the east side of the Raritan Valley along with Edison.