What is now Carteret was originally created as the borough of Roosevelt on April 11, 1906, from portions of Woodbridge Township, based on the results of a referendum approved on May 22, 1906. The name was changed to Carteret as of November 7, 1922. The borough was also called Carteret during the period from December 19, 1921, to January 16, 1922.
As of the census of 2000, there were 20,709 people, 7,039 households, and 5,208 families residing in the borough. The population density was 4,747.4 people per square mile (1,833.9/km²). There were 7,320 housing units at an average density of 1,678.1/sq mi (648.2/km²). The racial makeup of the borough was 68.76% White, 9.54% African American, 0.24% Native American, 8.32% Asian, 0.03% Pacific Islander, 9.26% from other races, and 3.86% from two or more races. Hispanic or Latino of any race were 23.37% of the population.
There were 7,039 households out of which 35.5% had children under the age of 18 living with them, 52.1% were married couples living together, 16.6% had a female householder with no husband present, and 26.0% were non-families. 21.9% of all households were made up of individuals and 11.1% had someone living alone who was 65 years of age or older. The average household size was 2.88 and the average family size was 3.38.
In the borough the population was spread out with 25.2% under the age of 18, 8.4% from 18 to 24, 30.0% from 25 to 44, 21.4% from 45 to 64, and 15.0% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 94.3 males. For every 100 females age 18 and over, there were 90.0 males.
The median income for a household in the borough was $47,148, and the median income for a family was $54,609. Males had a median income of $40,172 versus $28,132 for females. The per capita income for the borough was $18,967. About 8.6% of families and 11.0% of the population were below the poverty line, including 15.8% of those under age 18 and 9.4% of those age 65 or over.
Carteret has a large Punjabi Sikh population making up approx. 20% of the population. These numbers increased between 1999-2004. Two gurdwaras, Singh Sabha and Gurudwara Dashmesh Darbar Sahib (New Jersey), are located in Carteret. The Sikh community has dubbed Carteret as "Kartarpur", in remembrance of Guru Nanak, the founder of Sikhism. Kartarpur was the final resting place of Guru Nanak.
New Jersey Transit local bus service is provided on the 116 route to the Port Authority Bus Terminal in Midtown Manhattan and on the 62 route to Newark.