The area was inhabited by Native Americans for more than 2,800 years prior to exploration by Europeans. The first European settlements in this portion of New Jersey were established by the Swedes and Dutch in the early 1600s where a significant trade in furs existed between the natives and the Europeans at temporary posts. It became part of the Dutch colony of New Netherland, but the English seized control of the region in 1664, which was granted to Sir George Carteret and John Berkeley, 1st Baron Berkeley of Stratton, as the Province of New Jersey. In British colonial records, the first permanent European settlement at Morristown occurred in 1715, when a village was founded as New Hanover by migrants from New York and Connecticut. Morris County was created on March 15, 1739, from portions of Hunterdon County. The county was named for the popular Governor of the Province, Lewis Morris, who championed benefits for the colonists.
Following the American Revolution the former colony became the state of New Jersey and almost one hundred years after the American Revolution began, Morristown was incorporated as a town by an Act of the New Jersey Legislature on April 6, 1865, within Morris Township, and it was formally set off from the township in 1895.
As of the census of 2000, there were 18,544 people, 7,252 households, and 3,698 families residing in the town. The population density was 6,303.9 people per square mile (2,435.3/km²). There were 7,615 housing units at an average density of 2,588.7/sq mi (1,000.1/km²). The racial makeup of the town was 67.63% White, 16.95% Black or African American, 0.22% Native American, 3.77% Asian, 0.06% Pacific Islander, 8.48% from other races, and 3.36% from two or more races. Hispanic or Latino of any race were 27.15% of the population.
7.98% of Morristown residents identified themselves as being of Colombian American ancestry in the 2000 Census, the eighth highest percentage of the population of any municipality in the United States
There were 7,252 households out of which 22.5% had children under the age of 18 living with them, 34.4% were married couples living together, 12.0% had a female householder with no husband present, and 49.0% were non-families. 38.7% of all households were made up of individuals and 10.2% had someone living alone who was 65 years of age or older. The average household size was 2.43 and the average family size was 3.19.
In the town the population was spread out with 18.4% under the age of 18, 8.8% from 18 to 24, 40.4% from 25 to 44, 20.0% from 45 to 64, and 12.4% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 100.6 males. For every 100 females age 18 and over, there were 99.7 males.
The median income for a household in the town was $57,563, and the median income for a family was $66,419. Males had a median income of $42,363 versus $37,045 for females. The per capita income for the town was $30,086. About 7.1% of families and 11.5% of the population were below the poverty line, including 11.5% of those under age 18 and 14.3% of those age 65 or over.