Hartselle is the second largest city in Morgan County, Alabama, United States, 13 miles (21 km) south of Decatur.

[3] Hartselle was founded in 1869 with the arrival of the South and North Alabama Railroad.

U.S. Route 31 is the main north–south highway through the center of town, leading north 13 miles (21 km) to Decatur, the Morgan county seat, and south 20 miles (32 km) to Cullman.

Alabama State Route 36, Main Street, is the main east–west route through downtown, leading east 23 miles (37 km) to Lacey's Spring and west the same distance to Moulton.

[1] At the 2000 census there were 12,019 people, 4,816 households, and 3,534 families living in the city.

There were 5,170 housing units at an average density of 348.0 per square mile (134.4/km2).

At the 2010 census there were 14,255 people, 5,678 households, and 4,128 families living in the city.

There were 6,076 housing units at an average density of 407.8 per square mile (157.5/km2).

As of the 2020 United States census, there were 15,455 people, 5,518 households, and 3,930 families residing in the city.