Clifton was incorporated as a city by an Act of the New Jersey Legislature on April 26, 1917, replacing Acquackanonk Township, based on the results of a referendum held two days earlier. Clifton is listed under five different zip codes (07011, 07012, 07013, 07014, 07015).
As of the census of 2000, there were 78,672 people, 30,244 households, and 20,354 families residing in the city. The population density was 6,965.2 people per square mile (2,688.1/km²). There were 31,060 housing units at an average density of 2,749.9/sq mi (1,061.3/km²). The racial makeup of the city was 76.22% White, 2.89% African American, 0.24% Native American, 6.44% Asian, 0.03% Pacific Islander, 9.60% from other races, and 4.57% from two or more races. Hispanic or Latino of any race were 19.84% of the population.
There were 30,244 households out of which 28.9% had children under the age of 18 living with them, 51.3% were married couples living together, 11.5% had a female householder with no husband present, and 32.7% were non-families. 27.9% of all households were made up of individuals and 13.7% had someone living alone who was 65 years of age or older. The average household size was 2.59 and the average family size was 3.20.
In the city the population was 21.6% under the age of 18, 7.7% from 18 to 24, 30.7% from 25 to 44, 22.5% from 45 to 64, and 17.6% who were 65 years of age or older. The median age was 39 years. For every 100 females there were 91.4 males. For every 100 females age 18 and over, there were 88.1 males.
The median income for a household in the city was $50,619, and the median income for a family was $60,688. Males had a median income of $40,143 versus $32,090 for females. The per capita income for the city was $23,638. About 4.3% of families and 6.3% of the population were below the poverty line, including 8.6% of those under age 18 and 5.2% of those age 65 or over.
The largest ancestry groups in Clifton are Italian American (17%), Polish American (13%), Irish American (9%) and German American (8%). Many Turkish, Albanian, and Ukrainian immigrants also live in Clifton. There are significant populations of Hispanics, Arabs, Filipinos, Chinese, and Indians as well. Recent demographic changes include a substantial influx of Orthodox Jews in the areas bordering Passaic, a major orthodox enclave.