Newton was incorporated by an Act of the New Jersey Legislature on April 11, 1864 from portions of Newton Township, which was also partitioned to create Andover Township and Hampton Township, and was then dissolved. Additional land was acquired from Andover Township in 1869 and 1927, and from Fredon Township in 1920.
As of the census of 2000, there were 8,244 people, 3,258 households, and 1,941 families residing in the town. The population density was 2,661.7 people per square mile. There were 3,425 housing units at an average density of 1,105.8/sq mi. The racial makeup of the town was 91.97% White, 3.41% African American, 0.13% Native American, 1.97% Asian, 0.01% Pacific Islander, 1.16% from other races, and 1.35% from two or more races. Hispanic or Latino of any race were 3.80% of the population.
There were 3,258 households out of which 30.1% had children under the age of 18 living with them, 44.0% were married couples living together, 11.5% had a female householder with no husband present, and 40.4% were non-families. 33.5% of all households were made up of individuals and 14.5% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 3.12.
In the town, the population was spread out with 23.9% under the age of 18, 7.6% from 18 to 24, 31.2% from 25 to 44, 21.6% from 45 to 64, and 15.6% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 92 males. For every 100 females age 18 and over, there were 90.5 males.
The median income for a household in the town was $44,667, and the median income for a family was $56,484. Males had a median income of $41,089 versus $30,016 for females. The per capita income for the town was $20,577. About 6.9% of families and 11.2% of the population were below the poverty line, including 11.4% of those under age 18 and 11% of those age 65 or over.
Newton Airport is a public-use airport located 3 miles (4.8 km) south of the central business district.