Founded in 1718, the City of Perth Amboy is located at the mouth of the Raritan River and is surrounded on three sides by water – the Raritan River to the south and the Arthur Kill to the north and east. The city is neighbored by Woodbridge to the west. With 52,000 people in about six square miles, Perth Amboy is the sixth most populous municipality in Middlesex County and the most densely populated. Thomas Mundy Peterson was the first African American to vote under the 15th Amendment. Thomas Mundy Peterson voted in a local election held at Perth Amboy City Hall on March 31, 1870.