According to the U.S. Census Bureau, the city has a total area of 9.0 square miles (23.3 km²), of which, 9.0 square miles (23.2 km²) of it is land and 0.1 square miles (0.1 km²) of it (0.55%) is water.
Alabama's highest point, Mount Cheaha, is located several miles north of Lineville on Alabama Highway 49.
There were 1,004 households out of which 28.8% had children under the age of 18 living with them, 46.5% were married couples living together, 15.8% had a female householder with no husband present, and 33.7% were non-families. 31.2% of all households were made up of individuals and 15.7% had someone living alone who was 65 years of age or older. The average household size was 2.38 and the average family size was 2.97.
In the city the population was spread out with 25.5% under the age of 18, 8.9% from 18 to 24, 24.8% from 25 to 44, 22.1% from 45 to 64, and 18.6% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 87.0 males. For every 100 females age 18 and over, there were 80.8 males.
The median income for a household in the city was $23,468, and the median income for a family was $31,326. Males had a median income of $24,620 versus $18,024 for females. The per capita income for the city was $13,568. About 18.7% of families and 26.6% of the population were below the poverty line, including 41.4% of those under age 18 and 20.0% of those age 65 or over.