Morris County was the sixth-wealthiest county in the United States by median household income, and ranked tenth by per capita income. It is the ninth-wealthiest county in the United States by personal per-capita income, the highest rank in New Jersey. The county ranked third in the New York Metropolitan area in terms of median income.
As of the census of 2000, there were 470,212 people, 169,711 households, and 124,907 families residing in the county. The population density was 1,003 people per square mile (387/km²). There were 174,379 housing units at an average density of 372 per square mile (144/km²). The racial makeup of the county was 87.20% White, 2.80% Black or African American, 0.12% Native American, 6.26% Asian, 0.04% Pacific Islander, 2.01% from other races, and 1.56% from two or more races. 7.79% of the population were Hispanic or Latino of any race. 21.5% were of Italian, 14.5% Irish, 10.6% German, 5.5% Polish and 5.5% English ancestry according to Census 2000.
In 2005 78.5% of Morris County's population was non-Hispanic whites. African Americans constituted 3.1% of the population. 8.0% of the population was Asian. 1.0% of the population reported two or more races. These figures did not include any people in the category "Some other race". Latinos were 9.7% of the population, all except 0.5% of whom classified as white..
In 2000 There were 169,711 households out of which 35.40% had children under the age of 18 living with them, 62.80% were married couples living together, 7.90% had a female householder with no husband present, and 26.40% were non-families. 21.50% of all households were made up of individuals and 7.30% had someone living alone who was 65 years of age or older. The average household size was 2.72 and the average family size was 3.18.
In the county the population was spread out with 24.80% under the age of 18, 6.40% from 18 to 24, 31.90% from 25 to 44, 25.30% from 45 to 64, and 11.60% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 95.80 males. For every 100 females age 18 and over, there were 92.70 males.
Hispanics constituted a majority of the population in Dover and over a quarter of the people in Morristown; over 18% of Americans in Parsippany-Troy Hills are Asian Americans. There are fairly equal numbers of Irish American and German American residents. The Jewish American community is strong in specific areas, such as Randolph, Rockaway, and Morristown. Lincoln Park (26.7%), Montville (26.8%), East Hanover (41.8%), Pequannock Township (29.2%), and Riverdale (33.5%) have significant Italian American populations, along with other northern and eastern communities, while the rest of the county is more mixed with populations of Irish and German ancestries. Wharton (20.8%), Denville (25.1%), and Mine Hill (23.5%) are Irish American.
In 2009, Forbes magazine ranked the county sixth best place in the nation to raise a family. This was the best of any county in the state. The ranking was mainly due to the high graduation rate of 98>4%, employment possibilities from area industry.