The place name may be derived from the Lenape word "hòkèsa" meaning "pieces of bark" or from a misspelling of "occasion," as pronounced by the Quakers who settled the area originally.
According to the United States Census Bureau, the CDP has a total area of 10.0 square miles (26.0 km²), of which, 10.0 square miles (26.0 km²) of it is land and 0.10% is water.
There were 4,464 households out of which 40.1% had children under the age of 18 living with them, 77.3% were married couples living together, 4.5% had a female householder with no husband present, and 16.4% were non-families. 13.9% 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 2.83 and the average family size was 3.13.
In the CDP the population was spread out with 26.9% under the age of 18, 4.7% from 18 to 24, 24.5% from 25 to 44, 28.7% from 45 to 64, and 15.3% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 95.6 males. For every 100 females age 18 and over, there were 91.9 males.
The median income for a household in the CDP was $100,844, and the median income for a family was $108,784. Males had a median income of $76,617 versus $46,988 for females. The per capita income for the CDP was $40,516. About 1.0% of families and 1.7% of the population were below the poverty line, including 2.0% of those under age 18 and 1.3% of those age 65 or over.
Hockessin is one of the fastest growing areas in Delaware. Since 1990, the population has tripled.