The Chicago campus has existed in several forms over the years. It began at Navy Pier, and then later moved to what was called the Chicago Circle Campus. In 1982, the Circle Campus merged with the University of Illinois Medical Center campus to create the University of Illinois at Chicago.
The Chicago campus is home to the university system's medical school, which has satellite campuses in Rockford, Peoria, and Urbana. The Urbana school is considered a part of UIC despite being on the UIUC campus.
The Champaign-Urbana campus is the largest of the schools. It holds 18 schools, including a law, and aviation school. However, for those of us online, the most important facility of the institution is the National Center for Supercomputing Applications, NCSA. This was where, amongst others, Marc Andreesen (later of Netscape fame) helped forge the Mosaic web browser, the first HTML browser capable of rendering images. In addition, in 1987, NCSA created NCSA telnet, a program which permitted users access to the supercomputer's resources remotely.
Another campus is University of Illinois at Springfield