On January 19, 1883, the first electric lighting system employing overhead wires began service in Roselle, and was built by Thomas Edison, as part of an experiment to demonstrate that an entire community could be lit by electricity. The First Presbyterian Church, located on the corner of West 5th and Chestnut, was the first church in the world to be lit by electricity.
Roselle was incorporated on December 20, 1894, at the height of the Boroughitis phenomenon sweeping through New Jersey at the time, based on the results of a referendum held two days earlier, from portions of Linden.
As of the census of 2000, there were 21,274 people, 7,520 households, and 5,226 families residing in the borough. The population density was 8,048.8 people per square mile (3,111.3/km²). There were 7,870 housing units at an average density of 2,977.5/sq mi (1,151.0/km²). The racial makeup of the borough was 35.58% White, 51.32% African American, 0.31% Native American, 2.71% Asian, 0.07% Pacific Islander, 6.07% from other races, and 3.93% from two or more races. Hispanic or Latino of any race were 17.11% of the population.
There were 7,520 households out of which 32.2% had children under the age of 18 living with them, 45.3% were married couples living together, 18.8% had a female householder with no husband present, and 30.5% were non-families. 25.2% of all households were made up of individuals and 9.9% had someone living alone who was 65 years of age or older. The average household size was 2.82 and the average family size was 3.41.
In the borough the population was spread out with 25.5% under the age of 18, 9.4% from 18 to 24, 30.8% from 25 to 44, 22.2% from 45 to 64, and 12.0% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 87.9 males. For every 100 females age 18 and over, there were 82.8 males.
The median income for a household in the borough was $51,254, and the median income for a family was $58,841. Males had a median income of $37,604 versus $32,535 for females. The per capita income for the borough was $21,269. About 5.8% of families and 7.5% of the population were below the poverty line, including 8.5% of those under age 18 and 10.7% of those age 65 or over.
New Jersey Transit provides bus service to New York City and New Jersey points.
Conrail's freight-only Lehigh Line passes through the community along the tracks of the former Lehigh Valley Railroad. The town once shared a passenger station with Roselle Park on the mainline of the Central Railroad of New Jersey. That line is abandoned.
The Staten Island Railway passed through the community but is currently out of service.
Newark Liberty International Airport is approximately six miles from Roselle.