The Chicago Stock Exchange, located in Chicago, Illinois, is the third most active stock exchange in the United States by volume.
Founded on March 21, 1882, it merged with the St. Louis, Cleveland, and Minneapolis/St. Paul Stock Exchanges in 1949. Upon merger the Chicago Stock Exchange became the Midwest Stock Exchange. Ten years later, it absorbed the New Orleans Stock Exchange.
In 1993, the exchange changed its name back to the Chicago Stock Exchange.
http://www.chx.com