Adger is an unincorporated community in a coal-mining region of southwestern Jefferson County. The community is centered at the intersection of Mud Creek Road and Johns Road adjoining North Johns and Valley Creek alongside the Louisville & Nashville Railroad west of Bessemer.
The community was named for Andrew Adger, an executive of the DeBardeleben Coal and Iron Company. The Adger Post Office (ZIP code 35006) was established in 1889.
The Adger community had 3,109 residents according to the 2000 U.S. Census. Of those, 92% were white and 6.4% black. School age residents attend Oak Grove Elementary School and Oak Grove High School.
The Oak Grove Mine, Shoal Creek Mine, Shannon Mine, and Jim Walter #3 Mine are all active in the area around Adger.
On February 2, 2007 a Cessna 172 crashed between Adger and Mud Creek, killing a man and wife en route from their home in Hornersville, Missouri to Marathon, Florida.