Maplewood is home to approximately 41,000 people, with more than 15,000 households, according to 2018 U.S. Census estimates. The population density was 2,239.0 inhabitants per square mile (864.5/km2). There were 15,561 housing units at an average density of 916.4 per square mile (353.8/km2). The racial makeup of the city was 72.6% White, 7.97% African American, 0.42% Native American, 10.4% Asian, 0.1% Pacific Islander, 2.4% from other races, and 2.9% from two or more races. Hispanic or Latino of any race were 6.2% of the population.
There were 14,882 households of which 30.3% had children under the age of 18 living with them, 47.8% were married couples living together, 12.1% had a female householder with no husband present, 4.7% had a male householder with no wife present, and 35.4% were non-families. 29.1% of all households were made up of individuals and 12.5% had someone living alone who was 65 years of age or older. The average household size was 2.48 and the average family size was 3.08.
The median age in the city was 39.3 years. 22.9% of residents were under the age of 18; 9% were between the ages of 18 and 24; 25.2% were from 25 to 44; 27.7% were from 45 to 64; and 15.2% were 65 years of age or older. The gender makeup of the city was 48.0% male and 52.0% female.