Monroe Township is a township in Gloucester County, New Jersey, United States. As of the 2010 United States Census, the township's population was 36,129, reflecting an increase of 7,162 (+24.7%) from the 28,967 counted in the 2000 Census, which had in turn increased by 2,264 (+8.5%) from the 26,703 counted in the 1990 Census.
Monroe Township was originally formed as a township by an Act of the New Jersey Legislature on March 3, 1859, from portions of Washington Township, while the area was still part of Camden County. Monroe Township was shifted to Gloucester County on February 28, 1871, along with the majority of Washington Township. In 1950, portions of the township were transferred to Winslow Township in Camden County.
Victory Lakes (with a 2010 Census population of 2,111) and Williamstown (15,567 residents as of 2010) are census-designated places and unincorporated communities located within Monroe Township. Cross Keys is another unincorporated area within the township.