It was farmland from 1813 until the 1970s, eventually some of it was owned by James J. Douglas from 1896 until his death in 1917. Douglass Hills was incorporated in 1973 as the farmland was turned into subdivisions.
There were 2,428 households out of which 29.9% had children under the age of 18 living with them, 56.6% were married couples living together, 8.0% had a female householder with no husband present, and 33.0% were non-families. 27.9% of all households were made up of individuals and 8.9% had someone living alone who was 65 years of age or older. The average household size was 2.36 and the average family size was 2.89.
In the city the population was spread out with 22.4% under the age of 18, 7.7% from 18 to 24, 28.3% from 25 to 44, 28.0% from 45 to 64, and 13.6% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 94.8 males. For every 100 females age 18 and over, there were 91.6 males.
The median income for a household in the city was $60,021, and the median income for a family was $73,670. Males had a median income of $51,566 versus $31,196 for females. The per capita income for the city was $31,994. About 1.6% of families and 3.0% of the population were below the poverty line, including 2.3% of those under age 18 and 4.6% of those age 65 or over.