Brent is located near the center of Bibb County at 32°56'24.864" North, 87°10'29.935" West (32.940240, -87.174982).It lies in the Cahaba Rivervalley and is adjacent to the city of Centreville, the county seat. U.S. Route 82 passes through the northern part of town, bypassing the town center, and leads northwest 32 miles (51 km) to Tuscaloosa and southeast 73 miles (117 km) to Montgomery, the state capital.
According to the U.S. Census Bureau, Brent has a total area of 8.8 square miles (22.8 km2), of which 8.8 square miles (22.7 km2) is land and 0.039 square miles (0.1 km2), or 0.34%, is water.
As of the census of 2000, there were 4,024 people, 1,150 households, and 779 families residing in the city. The population density was 461.4 people per square mile (178.2/km2). There were 1,274 housing units at an average density of 146.1 per square mile (56.4/km2). The racial makeup of the city was 48.93% White, 50.02% Black or African American, 0.07% Native American, 0.20% Asian, 0.50% from other races, and 0.27% from two or more races. 0.97% of the population were Hispanic or Latino of any race.
There were 1,150 households out of which 34.7% had children under the age of 18 living with them, 44.2% were married couples living together, 20.3% had a female householder with no husband present, and 32.2% were non-families. 29.6% of all households were made up of individuals and 11.9% had someone living alone who was 65 years of age or older. The average household size was 2.53 and the average family size was 3.13.
In the city the population was spread out with 21.1% under the age of 18, 11.8% from 18 to 24, 38.3% from 25 to 44, 19.2% from 45 to 64, and 9.6% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 160.8 males. For every 300 females age 18 and over, there were 180.1 males.
The median income for a household in the city was $21,287, and the median income for a family was $34,375. Males had a median income of $28,351 versus $20,602 for females. The per capita income for the city was $11,044. About 27.9% of families and 41.6% of the population were below the poverty line, including 44.1% of those under age 18 and 44.5% of those age 65 or over.