Glen Ridge was incorporated as a borough by an Act of the New Jersey Legislature on February 13, 1895, from portions of Bloomfield Township, based on the results of a referendum held the previous day. In 1981, the name was changed to the "Township of Glen Ridge Borough" to take advantage of federal revenue sharing policies. Effective May 1993, it again became a borough.
Of the many legacies left to the town by its founders, the one that has become its trademark is the gas lamps. With only 3,000 gaslights remaining in operation in the entire United States, Glen Ridge has 665 such lamps lighting its streets. In 1924, Glen Ridge became the first municipality in New Jersey to establish a zoning ordinance.
As of the census of 2000, there were 7,271 people, 2,458 households, and 1,978 families residing in the borough. The population density was 5,695.0 people per square mile (2,193.2/km²). There were 2,490 housing units at an average density of 1,950.3/sq mi (751.1/km²). The racial makeup of the borough was 89.18% White, 4.98% African American, 0.15% Native American, 3.34% Asian, 0.99% from other races, and 1.36% from two or more races. Hispanic or Latino of any race were 3.45% of the population.
There were 2,458 households out of which 46.3% had children under the age of 18 living with them, 69.9% were married couples living together, 8.1% had a female householder with no husband present, and 19.5% were non-families. 16.7% of all households were made up of individuals and 8.0% had someone living alone who was 65 years of age or older. The average household size was 2.95 and the average family size was 3.33.
In the borough, the population was spread out with 30.7% under the age of 18, 4.5% from 18 to 24, 29.5% from 25 to 44, 24.9% from 45 to 64, and 10.4% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 94.9 males. For every 100 females age 18 and over, there were 89.3 males.
The median income for a household in the borough was $105,638, and the median income for a family was $120,650. Males had a median income of $91,161 versus $51,444 for females. The per capita income for the borough was $48,456. About 1.9% of families and 3.0% of the population were below the poverty line, including 3.3% of those under age 18 and 4.1% of those age 65 or over.