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 & 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.