As of the census of 2000, there were 18,188 people, 5,436 households, and 3,919 families residing in Dover. The population density was 6,788.2 people per square mile (2,620.3/km²). There were 5,568 housing units at an average density of 2,078.1/sq mi (802.2/km²). The racial makeup of the town was 69.45% White, 6.83% African American, 0.34% Native American, 2.47% Asian, 0.03% Pacific Islander, 15.99% from other races, and 4.89% from two or more races. Hispanic or Latino of any race were 57.94% of the population.
11.27% of Dover residents identified themselves as being of Colombian American ancestry in the 2000 Census, the second highest percentage of the population of any municipality in the United States (behind neighboring Victory Gardens, New Jersey which had 15.27% of residents so identified) with 1,000 residents identifying their ancestry.
There were 5,436 households out of which 35.7% had children under the age of 18 living with them, 50.2% were married couples living together, 13.5% had a female householder with no husband present, and 27.9% were non-families. 21.3% of all households were made up of individuals and 8.7% had someone living alone who was 65 years of age or older. The average household size was 3.29 and the average family size was 3.55.
In the town the population was spread out with 23.2% under the age of 18, 10.5% from 18 to 24, 36.0% from 25 to 44, 19.8% from 45 to 64, and 10.6% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 106.4 males. For every 100 females age 18 and over, there were 106.7 males.
The median income for a household in the town was $53,423, and the median income for a family was $57,141. Males had a median income of $31,320 versus $27,413 for females. The per capita income for the town was $18,056. About 8.2% of families and 13.4% of the population were below the poverty line, including 14.5% of those under age 18 and 7.1% of those age 65 or over.
Highways traveling in or nearby Dover include Interstate 80, U.S. Route 46, New Jersey Route 10 and New Jersey Route 15. Dover Exit 35 off of Route 80 is a popular stop for travelers, existing halfway between the Delaware Water Gap and New York City. The Rockaway Townsquare Mall rests immediately off the exit.
Dover is served by Morris County Metro bus routes 2 & 10 providing service to Randolph, Rockaway, Morris Plains, Victory Gardens, Wharton, Morristown, and intermediate points. Buses on the #10 route make stops along Blackwell Street. while the #2 route operates via Penn Avenue, Morris Street, Blackwell Street, and Salem Street.
NJ Transit's Morristown Line and Montclair-Boonton Line stop at the Dover train station. Trains operate to Hackettstown, Netcong, Boonton, Morristown, Montclair State University, Summit, the Oranges, Newark, Hoboken, New York City, and intermediate points.
Lakeland Bus Lines provides regular service to Sparta, Newton, Mount Olive, Rockaway, Boonton, Parsippany, Wayne, New York City, and intermediate points from their terminal on the Rockaway Township border. Service is also provided from Wednesday to Sunday between Dover and Atlantic City
Dover is served by numerous local taxi services. Taxis can be found waiting outside of the supermarkets, bars, bus stations, and train station. The town has made efforts to control the amount of taxis operating in the town and passed an ordinance limiting the number of taxis to 60. However, some companies have set up in neighboring towns to avoid the ordinance.
Dover is located approximately 15 minutes west of Morristown Municipal Airport, and approximately 40 minutes west Liberty International Airport in Newark, NJ.