Illinois Watch Co, initially known as the Springfield Watch Company, began operations in 1870 on a 14 acre site on Springfield's north end between 9th & 11th Streets and North Grand & Converse. In 1928, the company was sold to Hamilton Watch Company of Pennsylvania and by 1932, the Springfield plant was closed having made six million watches in its 61 year history. In its most profitable years, Illinois Watch Company employeed more than 1,200 people. Sangamo Electric, a subsidiary of Illinois Watch Co, bought the factory site and began making electric meters but in 1978, Sangamo was sold to an international company. Through the years, factory buildings were razed and new, modern offices were built.

The "ILLINOIS WATCH CO" letters were donated to us in 2020 and restored and placed in our museum. They are believe to be from the companies founding in 1870. We have the other letters in storage, except for a missing letter in "ILLINOIS" which was kept by the donor.