Alagasco has been providing reliable natural gas service in Alabama for more than 150 years. A subsidiary of Energen Corporation, Alagasco traces its beginning to 1852 when the company was known as the Montgomery Gas Light Company. At the beginning, the company was responsible for providing street lighting in Montgomery, Alabama using manufactured gas. Through a series of relocations, mergers, acquisitions, divestitures and name changes Alabama Gas Company (Alagasco) emerged in 1948.

Alagasco is the largest natural gas distributor in the state and serves approximately 437,000 customers in over 200 Alabama cities, town and communities. More than 1,000 employees work in Alagasco's offices across the state.