The Illinois Watch Case Company was incorporated in August 1888 by Thomas Duncan, Paul Brown, and David J. Wile with a capital stock of $50,000 (some documents indiate a date of November 24, 1888). The company was headquartered in Chicago, Illinois and sustained fire damage in 1889, possibly prompting a decision to relocate the factory to Elgin, Illinois.

One of the first cases offered on the market by the new company was the "Commander."

As the new factory was being built, the company chose to rebrand as the Elgin Nation Watch Case Company. However, the Elgin National Watch Company quickly objected to the name. As a result, the company was reorganized as the Elgin Watch Case Company. This move attracted legal disputes from the Elgin National Watch Company.

By June 1890, the case factory in Elgin was put in motion with 100 workers, led by Max C. Eppenstein. By the following year, more than 200 were employed at the factory.

In April 1892, the Elgin National Watch Case Company was incorporated with a capital stock of $250,000, hoping to establish rights to the tradename.

In December 1892, Judge Horton decided that the case company could not use the Elgin name. As a result, the company readopted the previous company name, the Illinois Watch Case Company.

Despite the name change, the company continued to use "Elgin" in product names, advertising case grades like "Elgin Pride," "Elgin Commander," "Elgin Giant," and "Elgin Tiger."

In 1895, the company ventured into the new bicycle trend by organizing the Elgin Cycle Company, and part of the case factory was utilized to manufacture bicycles.

The legal complaints from the Elgin National Watch Company continued in an attempt to protect the "Elgin" name. In March 1898, Judge Showalter decided that the Illinois Watch Case Company could no longer use the word "Elgin" to promote their products.

Shortly after, in September 1898, President Thomas W. Duncan resigned his position at the Illinois Watch Case Company.

In 1898, the company organized subsidiary - The Elgin American Manufacturing Company - to manufacture vainty cases, cigarette cases, lockets, and other small jewelry items.

In 1901, the company introduced its Nubian case, advertised as the only gunmetal watch case on the market. The company also expanded by creating a line of fancy solid gold cases and purchasing the Rockford Watch Company.

In 1910, the "Elgin Giant Watch Case Company" was organized to facilitate sales of cases for the Illinois Watch Case Company in foreign markets. While the "Elgin Giant" grade had existed previously and was continued after this point, any case marked "Elgin Giant Watch Case Co." was produced after 1910.

Around 1912, the name "Elgin Giant Watch Case Company" began to appear in some American advertisements and industry publications, usually promoting solid gold cases. This company name was utilized in addition to the Illinois Watch Case Company name, as evidenced by the 1924 notice published by various case companies agreeing not to mark cases with guarantees.

In the late 1910s and 1920s, the "Elgin Giant Watch Case Company" name was utilized more frequently for fancier cases in the Illinois product line, presumably abandoning the original intention to use the name exclusively in foreign markets.

In 1955, the Illinois Watch Case Company decided to exapnd into additional jewelry products. The following year, the company reorganized as Elgin American Inc., and the Illinois Watch Case Company became a division of the parent company with the intent to close out the case manufacturing operation.

In 1957, the company liquidated the remaining case tools and machinery at auction.