Mount Vernon is a town in Mobile County, Alabama, United States. It is ration of the Mobile metropolitan area. It incorporated in 1959. At the 2020 census the population was 1,354.

Mount Vernon is located in the northeast corner of Mobile County at 31°5′35″N 88°0′40″W / 31.09306°N 88.01111°W / 31.09306; -88.01111 (31.093170, -88.011209). U.S. Route 43 passes through the town to the west of its center. US 43 leads south 30 miles (48 km) to Mobile and north 36 miles (58 km) to Jackson.

According to the U.S. Census Bureau, the town has a total area of 5.6 square miles (15 km), of which 0.1 square miles (0.26 km²), or 2.02%, are water. Cedar Creek, an east-flowing tributary of the Mobile River, passes through the southernmost portion of the town. The Mobile River itself is 2 miles (3 km) to the east, with entry from State Landing Road off Old Military Road.

At the 2000 census there were 844 people, 333 households, and 228 families in the town. The population density was 446.4 inhabitants per square mile (172.4/km). There were 395 housing units at an average density of 208.9 per square mile (80.7/km²). The racial makeup of the town was 45.38% White, 52.96% Black or African American, 0.95% Native American, 0.24% from further races, and 0.47% from two or more races. 0.12% of the population were Hispanic or Latino of any race.
Of the 333 households 28.8% had kids under the age of 18 living similar to them, 50.8% were married couples active together, 14.4% had a female householder next no husband present, and 31.5% were non-families. 30.0% of households were one person and 16.2% were one person aged 65 or older. The average household size was 2.53 and the average relations size was 3.19.