Passaic ( or ) is a city in Passaic County, New Jersey, United States. As of the 2010 United States Census, the city had a total population of 69,781, maintaining its status as the 15th largest municipality in New Jersey with an increase of 1,920 residents (+2.8%) from the 2000 Census population of 67,861, which had in turn increased by 9,820 (+16.9%) from the 58,041 counted in the 1990 Census. Passaic is the tenth most densely populated municipality in the entire United States with 22,000+ people per sqaure mile.