There were 6,172 housing units at an average density of 341 per square mile (132/km²). The racial makeup of the town was 96.0% White, 0.70% African American, 0.1% Native American, 1.0% Asian, 0.0% Pacific Islander, 0.7% from other races, and 1.5% from two or more races. Hispanic or Latino of any race were 3.1% of the population. There were 5,896 households out of which 34.1% had children under the age of 18 living with them, 53.8% were married couples living together, 11.1% had a female householder with no husband present, 4.6% had a male householder with no wife present, and 30.5% were non-families. 24.7% of all households were made up of individuals and 9.6% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.1. In the town, the population was spread out with 27.5% under the age of 18, 6.1% from 18 to 24, 31.3% from 25 to 44, 21.4% from 45 to 64, and 13.8% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 90.8 males. For every 100 females age 18 and over, there were 86.7 males. The median income for a household in the town was $68,981, and the median income for a family was $87,359. Males had a median income of $57,076 versus $44,825 for females. The per capita income for the town was $30,945. About 4.6% of families and 4.8% of the population were below the poverty line, including 3.6% of those under age 18 and 5.8% of those age 65 or over. Situated between Interstates 90 (Mass Pike), 146, 395, and 495, Northbridge has highway access to and from major cities such as Worcester, Providence and Boston. Route 146 has a small portion in the town. Also, Route 122 runs along Providence Road. The nearest commuter rail station into Boston is located in nearby Grafton, approximately 9 miles away. The town is located equidistantly (approx. 10–12 miles) between the Franklin/495/Forge Park T-station and the Worcester T-station, both with ample parking.