According to the United States Census Bureau, Richwood has a total area of 3.1 square miles (8.1 km2), of which 3.1 square miles (8.0 km2) is land and 0.04 square miles (0.1 km2), or 1.30%, is water.[4]
As of the 2020 United States census, there were 4,781 people, 1,438 households, and 889 families residing in the city.
As of the census[2] of 2000, there were 3,012 people, 1,138 households, and 825 families residing in the city. The population density was 1,922.5 inhabitants per square mile (742.3/km2). There were 1,254 housing units at an average density of 800.4 per square mile (309.0/km2). The racial makeup of the city was 78.19% White, 8.50% African American, 0.37% Native American, 0.50% Asian, 0.07% Pacific Islander, 9.26% from other races, and 3.12% from two or more races. Hispanic or Latino of any race were 23.37% of the population.
There were 1,138 households, out of which 40.3% had children under the age of 18 living with them, 58.2% were married couples living together, 9.9% had a female householder with no husband present, and 27.5% were non-families. 22.8% of all households were made up of individuals, and 2.5% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.13.
In the city, the population was spread out, with 28.8% under the age of 18, 12.8% from 18 to 24, 31.9% from 25 to 44, 20.6% from 45 to 64, and 6.0% who were 65 years of age or older. The median age was 29 years. For every 100 females, there were 99.3 males. For every 100 females age 18 and over, there were 98.6 males.
The median income for a household in the city was $45,000, and the median income for a family was $54,280. Males had a median income of $39,911 versus $22,773 for females. The per capita income for the city was $19,181. About 9.1% of families and 10.5% of the population were below the poverty line, including 13.0% of those under age 18 and 1.7% of those age 65 or over.
^Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race.[8][9]