Passaic is a city in Passaic County, in the U.S. state of New Jersey. As of the 2020 United States census, the city was the state's 16th-most-populous municipality, with a population of 70,537, falling behind Bayonne, an increase of 756 (+1.1%) from the 2010 census count of 69,781, which in turn reflected an increase of 1,920 residents (+2.8%) from the 2000 census population of 67,861. The Census Bureau's Population Estimates Program calculated that the city's population was 69,128 in 2022, ranking the city the 546th-most-populous in the country. Among cities with more than 50,000 people, Passaic was the fifth-most densely populated municipality in the United States, with more than 22,000 people per square mile.

Albert Weisbord (1900–1977) was an American political activist and union organizer. He is best remembered, along his wife Vera Buch, as one of the primary union organizers of the seminal 1926 Passaic Textile Strike and as the founder of a small Trotskyist political organization of the 1930s called the Communist League of Struggle.