Columbia Gas

About Columbia Gas of Massachusetts Columbia Gas of Massachusetts delivers clean, affordable and efficient natural gas to over 320,000 natural gas customers in southeastern Massachusetts, the greater Springfield area and the Merrimack Valley. Headquartered in Westborough, Massachusetts, the company is the largest gas-only provider in the state and 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.