Commonwealth Edison

Commonwealth Edison, commonly known by syllabic abbreviation as ComEd, is the largest electric utility in Illinois, and the primary electric provider in Chicago and much of Northern Illinois. Its service territory stretches roughly from Iroquois County on the south to the Wisconsin border on the north and from the Iowa border on the west to the Indiana border on the east. For more than 100 years, Commonwealth Edison has been the primary electric delivery services company for Northern Illinois. Today, ComEd is a unit of Chicago-based Exelon Corporation, one of the nation's largest electric and gas utility holding companies. ComEd provides electric service to more than 3.8 million customers across Northern Illinois. The company's revenues totaled more than $7 billion in 2023. As of 2015, ComEd has interconnections with We Energies, ITC Midwest, Ameren, American Electric Power, Northern Indiana Public Service, and MidAmerican Energy Company (MEC).