Vectren Corporation is a Fortune 1000 energy holding company headquartered in Evansville, Indiana. Through its utility subsidiaries (Vectren North, Vectren South, and Vectren Energy Delivery of Ohio), the company distributes natural gas to approximately one million business and residential customers in Indiana and Ohio. It also distributes electricity to 141,000 customers and has 1,425 MW of primarily coal-fired generating capacity in Indiana. Vectren's nonutility subsidiaries and affiliates currently offer energy-related products and services to customers throughout the Midwest and Southeast. These include energy performance services and energy infrastructure services.

The company was formed from the merger of Indiana Gas Company (formed 1941) and Southern Indiana Gas and Electric Company (SIGECO, formed 1912). The two utilities' holding companies, Indiana Energy and SIGCORP, announced plans to merge in June 1999, and received final approval on March 9, 2000. In the fall of 2000, Vectren also acquired the natural gas distribution assets of Dayton Power and Light in western Ohio. In the fall of 2006, the company purchased Duke Energy's interest in Miller Pipeline.

In a 2010 reorganization, Indiana Gas was renamed Vectren North, while SIGECO was renamed Vectren South.

Vectren's largest subsidiary, Vectren Utility Holdings, oversees Vectren Energy Delivery of Indiana - North (Vectren North—the former Indiana Gas), Vectren Energy Delivery of Indiana - South (Vectren South—the former SIGECO) and Vectren Energy Delivery of Ohio (VEDO).

Vectren provides natural gas to 680,000 customers in Indiana (570,000 in central Indiana and 110,000 in southwestern Indiana) and 314,000 customers in Ohio. It provides electricity to 142,000 customers in southwestern Indiana.

Vectren's nonutility group consists of three divisions Infrastructure Services, Energy Services, and Coal Mining. Vectren also operates a nonprofit foundation, the Vectren Foundation, which provides assistance for community development and energy efficiency projects.

Vectren sponsors the radio network of the Indianapolis Colts NFL football team; the network is referred to on-air as the "Vectren Radio Network". Vectren also sponsors the annual "Vectren Dayton Air Show"

On January 29, 2003, Vectren restated its 2001 earnings. As a result of adjustments related to gas and employee benefit costs, 2001 earnings previously reported were reduced by 18 cents per share. Vectren has installed the Healthcare Bluebook and Grand Rounds to reduce employee healthcare cost inflation.