Little Falls is a township in Passaic County, in the U.S. state of New Jersey. The township was named after a waterfall on the Passaic River at a dam near Beattie Mill. As of the 2020 United States census, the township's population was 13,360, a decrease of 1,072 from the 2010 census count of 14,432, which in turn reflected an increase of 3,577 f…Little Falls is a township in Passaic County, in the U.S. state of New Jersey. The township was named after a waterfall on the Passaic River at a dam near Beattie Mill. As of the 2020 United States census, the township's population was 13,360, a decrease of 1,072 from the 2010 census count of 14,432, which in turn reflected an increase of 3,577 from the 10,855 counted in the 2000 census.