Columbia Gas of Kentucky delivers clean, affordable and efficient natural gas to approximately 135,000 customers across the state. Headquartered in Lexington, it is one of NiSource’s seven regulated utility companies. NiSource (NYSE: NI) is one of the largest fully-regulated utility companies in the united states, serving approximately 3.5 million natural gas customers and 500,000 electric customers through its local Columbia Gas and NIPSCO brands.