The Illinois State Bar Association (ISBA) is among the largest voluntary state bar associations in the United States. Approximately 28,000 lawyers are members of the ISBA. Unlike some state bar associations, in which membership is mandatory, ISBA membership is not required of lawyers licensed to practice in Illinois and ISBA membership is completely voluntary. The ISBA is headquartered in Springfield, Illinois. It also has an office in Chicago, Illinois.
^"About Us". Illinois State Bar Association. Retrieved 2012-08-05.