Prospect Heights is a city in Cook County, Illinois, United States and is a suburb of Chicago. Per the 2020 census, the population was 16,058.

According to the 2021 census gazetteer files, Prospect Heights has a total area of 4.29 square miles (11.11 km2), of which 4.26 square miles (11.03 km2) (or 99.30%) is land and 0.03 square miles (0.08 km2) (or 0.70%) is water

As of the 2020 census there were 16,058 people, 6,144 households, and 4,205 families residing in the city. The population density was 3,746.62 inhabitants per square mile (1,446.58/km2). There were 6,657 housing units at an average density of 1,553.20 per square mile (599.69/km2). The racial makeup of the city was 61.41% White, 10.31% Asian, 1.51% African American, 1.33% Native American, 0.01% Pacific Islander, 14.14% from other races, and 11.30% from two or more races. Hispanic or Latino of any race were 28.99% of the population

There were 6,144 households, out of which 29.2% had children under the age of 18 living with them, 52.70% were married couples living together, 10.34% had a female householder with no husband present, and 31.56% were non-families. 25.00% of all households were made up of individuals, and 11.74% had someone living alone who was 65 years of age or older. The average household size was 3.09 and the average family size was 2.59.

The city's age distribution consisted of 24.0% under the age of 18, 5.4% from 18 to 24, 29% from 25 to 44, 23.6% from 45 to 64, and 18.1% who were 65 years of age or older. The median age was 38.7 years. For every 100 females, there were 109.7 males. For every 100 females age 18 and over, there were 100.0 males.

The median income for a household in the city was $72,500, and the median income for a family was $84,803. Males had a median income of $48,699 versus $27,007 for females. The per capita income for the city was $39,534. About 6.5% of families and 10.0% of the population were below the poverty line, including 13.8% of those under age 18 and 7.0% of those age 65 or over