Millville was originally incorporated as a township by an Act of the New Jersey Legislature on February 24, 1801, from portions of Fairfield Township. Portions of the township were taken to form Landis Township on March 7, 1864. Millville was reincorporated as a city on March 1, 1866, based on the results of a referendum passed that same day.
The census of 2000 concluded, There were 26,847 people, 10,043 households, and 7,010 families residing in the city. The population density was 633.9 people per square mile (244.8/km²). There were 10,652 housing units at an average density of 251.5/sq mi (97.1/km²). The racial makeup of the city was 76.13% White, 14.99% African American, 0.52% Native American, 0.80% Asian, 0.03% Pacific Islander, 5.16% from other races, and 2.37% from two or more races. Hispanic or Latino of any race were 11.17% of the population.
There were 10,043 households out of which 35.0% had children under the age of 18 living with them, 46.5% were married couples living together, 17.9% had a female householder with no husband present, and 30.2% were non-families. 25.1% of all households were made up of individuals and 11.6% had someone living alone who was 65 years of age or older. The average household size was 3.65 and the average family size was 2.15.
In the city the population was spread out with 27.9% under the age of 18, 8.6% from 18 to 24, 28.8% from 25 to 44, 21.7% from 45 to 64, and 12.9% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 89.5 males. For every 100 females age 18 and over, there were 85.3 males.
The median income for a household in the city was $40,378, and the median income for a family was $46,093. Males had a median income of $36,915 versus $26,669 for females. The per capita income for the city was $18,632. About 12.1% of families and 15.2% of the population were below the poverty line, including 21.8% of those under age 18 and 9.7% of those age 65 or over.
Route 47, Route 49 and Route 55 all pass through the city.
Millville Municipal Airport, operated by the Delaware River and Bay Authority, serves general aviation.
NJ Transit has several bus routes that service the Millville region.