This company traces its origins to some of the gas companies founded in northern Illinois during the 1850s, such as the Ottawa Gas Light & Coke Co. The first steps toward the formation of the large company that eventually became Nicor occurred during the early 1910s. In 1911, a group of investors including Chicago utilities titan Samuel Insull created the Public Service Co. of Northern Illinois; one year later, a different merger of small gas companies in the region created the Illinois Northern Utilities Co. These two entities were united in 1954 as Northern Illinois Gas, which had about $60 million in sales during its first year. By the early 1960s, the company employed about 3,600 people around the region. In 1976, Northern Illinois Gas became a subsidiary of Nicor Inc., a holding company. By the early 2000s, Naperville-based Nicor had revenues approaching $2 billion and still employed some 3,500 people.

This entry is part of the Encyclopedia's Dictionary of Leading Chicago Businesses (1820-2000) that was prepared by Mark R. Wilson, with additional contributions from Stephen R. Porter and Janice L. Reiff.