NiSource is the main energy source for resourceful Americans living in the Midwest, the South, and New England. The company's utility subsidiaries distribute natural gas to about 3.5 million customers in seven states. NiSource also generates, transmits, and distributes power to some 500,000 customers in 20 counties in its home state through its largest subsidiary, Northern Indiana Public Service Company (NIPSCO). NiSource owned one of the largest natural gas transmission and underground storage systems in the US, including a more than 15,000-mile interstate pipeline system. However, to become a pure play utility group, it spun off this business in 2015.