Richwood is an unincorporated community and census-designated place (CDP) located in Gloucester County, in the U.S. state of New Jersey, that is split between Harrison Township (with 3,400 of the CDP's residents) and Mantua Township (with 59 of the total).

[9] As of the 2020 United States census, the CDP’s population was 3,577, an increase of 118 (+3.4%) from the 3,459 enumerated at the 2010 U.S.

[5][13] The 2010 United States census counted 3,459 people, 1,055 households, and 902 families in the CDP.

There were 1,101 housing units at an average density of 124.4 per square mile (48.0/km2).

Of all households, 11.9% were made up of individuals and 4.5% had someone living alone who was 65 years of age or older.