Commonwealth Edison, commonly known as ComEd, is the largest electric utility in Illinois, serving the Chicago and Northern Illinois area. The service territory roughly borders in Iroquois County to the south, the Wisconsin border to the north, the Iowa border to the west, and the Indiana border to 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 (NYSE: EXC), 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.