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. The Census Bureau's Population Estimates Program calculated that the city's population was 69,703 in 2019, ranking the city the 524th-most-populous in the country. Among cities with more than 50,000 people, Passaic is the fifth-most-densely-populated municipality in the United States, with more than 22,000 people per square mile.