Our History

Through its predecessor company, Hartford City Light, Connecticut Natural Gas (CNG) has served central Connecticut for more than 160 years.

In 2010, CNG and its sister companies, Southern Connecticut Gas and Berkshire Gas of Massachusetts, became subsidiaries of UIL Holdings Corporation.

UIL Holdings merged in 2015 with the U.S. holdings of Iberdrola, S.A. to form AVANGRID, Inc. (NYSE: AGR), a diversified energy and utility company with two primary lines of business in 27 states.

CNG is proud to be part of the AVANGRID family of companies and shares its commitment to providing clean energy and reliable delivery to customers through innovative technology and sound investment in infrastructure.