According to the Washington State Office of Financial Management, DuPont ranked 3rd of 279 eligible incorporated communities in population growth between 2000 and 2005.
The first school was established in 1852, and in 1869, the federal government auctioned the site off to settlers. In 1906, the DuPont company purchased a 5 mi² area for construction of an explosives plant. By 1909, the company town had more than 100 houses.
DuPont was officially incorporated on March 26, 1912, and was re-incorporated in 1951. DuPont has recently undergone a modern transformation as the planned annexed community of Northwest Landing, Washington has been realized. The city is expected to have a built out population of 12,000.
Wilmington Street and McNeil Street are the two main roads that pass through the downtown area of DuPont. Several businesses in DuPont have opened in the last five years. Historic Village, a residential area, is the only part of DuPont that is not part of Northwest Landing.
According to the United States Census Bureau, the city has a total area of 5.7 square miles (14.8 km²), of which, 5.7 square miles (14.7 km²) of it is land and 0.04 square miles (0.1 km²) of it (0.35%) is water.
There were 936 households out of which 40.1% had children under the age of 18 living with them, 63.8% were married couples living together, 6.0% had a female householder with no husband present, and 28.4% were non-families. 23.2% of all households were made up of individuals and 3.7% had someone living alone who was 65 years of age or older. The average household size was 2.61 and the average family size was 3.12.
In the city the population was spread out with 29.9% under the age of 18, 5.0% from 18 to 24, 40.8% from 25 to 44, 17.8% from 45 to 64, and 6.5% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 93.7 males. For every 100 females age 18 and over, there were 94.2 males.
The median income for a household in the city was $52,969, and the median income for a family was $57,202. Males had a median income of $42,946 versus $36,741 for females. The per capita income for the city was $22,742. About 2.2% of families and 4.6% of the population were below the poverty line, including 3.5% of those under age 18 and 2.5% of those age 65 or over.