According to the United States Census Bureau, the city has a total area of 13.2 square miles (34.1 km²), of which, 12.5 square miles (32.3 km²) of it is land and 0.7 square miles (1.7 km²) of it (5.09%) is water.
There were 4,742 households out of which 37.3% had children under the age of 18 living with them, 49.9% were married couples living together, 16.1% had a female householder with no husband present, and 30.0% were non-families. 24.6% of all households were made up of individuals and 10.6% had someone living alone who was 65 years of age or older. The average household size was 2.69 and the average family size was 3.23.
In the city the population was spread out with 26.9% under the age of 18, 18.4% from 18 to 24, 26.5% from 25 to 44, 17.1% from 45 to 64, and 11.1% who were 65 years of age or older. The median age was 28 years. For every 100 females there were 95.0 males. For every 100 females age 18 and over, there were 90.4 males.
The median income for a household in the city was $32,052, and the median income for a family was $38,635. Males had a median income of $31,304 versus $20,678 for females. The per capita income for the city was $14,345. About 12.7% of families and 17.9% of the population were below the poverty line, including 20.7% of those under age 18 and 14.0% of those age 65 or over.
For recreation, Belton has two major lakes: Belton Lake and Stillhouse Hollow Lake. There is also a water park, Summer Fun Water Park Another notable recreation point is BLORA which is part of Ft. Hood and is located on Lake Belton
Actor George Eads grew up in Belton. He graduated from Belton High School in 1985.
Alternative rock band Flyleaf is from Belton.
The town did not get a Wal-Mart Supercenter until 2005.
Rapper/Producer Noki Swazay hails from Belton and has a tattoo of the iconic Belton Water Tower on his right arm.
Historian and rancher J. Evetts Haley was born in Belton and is buried beside his first wife, Nita Stewart Haley, in the Moffat Cemetery. However, he spent most of his life in Midland and Canyon in West Texas.
Home of the Texas Rodeo Cowboy Hall of Fame housed in the Bell County Expo Center.