Belle is located at . According to the United States Census Bureau, the city has a total area of, all land. Belle is approximately west southwest of St. Louis. The Gasconade River flows past the community, about six miles to the west.
As of the census of 2010, there were 1,545 people, 659 households, and 408 families living in the city. The population density was. There were 734 housing units at an average density of. The racial makeup of the city was 97.5% White, 0.2% African American, 0.1% Native American, 0.6% from other races, and 1.6% from two or more races. Hispanic or Latino of any race were 1.4% of the population. There were 659 households, of which 33.1% had children under the age of 18 living with them, 41.0% were married couplesliving together, 15.2% had a female householder with no husband present, 5.8% had a male householder with no wife present, and 38.1% were non-families. 33.1% of all households were made up of individuals, and 17% had someone living alone who was 65 years of age or older. The average household size was 2.34 and the average family size was 2.91. The median age in the city was 36.2 years. 26.7% of residents were under the age of 18; 8.6% were between the ages of 18 and 24; 24.4% were from 25 to 44; 24.5% were from 45 to 64; and 15.7% were 65 years of age or older. The gender makeup of the city was 48.6% male and 51.4% female.
2000 census
As of the census of 2000, there were 1,344 people, 595 households, and 357 families living in the city. The population density was 1,062.1 people per square mile. There were 652 housing units at an average density of 515.2 per square mile. The racial makeup of the city was 97.10% White, 0.07% African American, 0.52% Native American, 0.60% from other races, and 1.71% from two or more races. Hispanic or Latino of any race were 1.12% of the population. There were 595 households, out of which 29.9% had children under the age of 18 living with them, 41.3% were married couples living together, 13.6% had a female householder with no husband present, and 40.0% were non-families. 36.0% of all households were made up of individuals, and 19.5% had someone living alone who was 65 years of age or older. The average household size was 2.23 and the average family size was 2.83. In the city, the population was spread out, with 26.0% under the age of 18, 10.2% from 18 to 24, 24.9% from 25 to 44, 20.2% from 45 to 64, and 18.8% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 82.9 males. For every 100 females age 18 and over, there were 74.6 males. The median income for a household in the city was $24,091, and the median income for a family was $35,982. Males had a median income of $27,917 versus $17,857 for females. The per capita income for the city was $17,785. About 14.7% of families and 19.3% of the population were below the poverty line, including 31.3% of those under age 18 and 15.2% of those age 65 or over.
