In 1969, Governor Richard Ogilvie signed into law a bill officially creating Sangamon State University.

It originally operated as an "upper-division" university—that is, a university that offers only the last two years of undergraduate education, as well as graduate work.

Sangamon State aimed to be a "truly pioneering segment of public education" through a spirit of openness, innovation and adaptability.

In 1995, Governor Jim Edgar signed a bill which abolished the Board of Regents and merged SSU with the University of Illinois system.

The Thomas Strawbridge homestead, constructed around 1845, still stands on the south edge of the University of Illinois Springfield campus and was restored in 2012.

[6] These buildings were the first part of a master plan of 1970–1971 that called for an "urban campus" surrounded by restored prairie land, free of all vehicular traffic and easily navigable by pedestrians.

Routes 11, 15, and 905 provide bus service from campus to the Lincoln Land Community College and to downtown Springfield.

The university is a member of the Division II level of the National Collegiate Athletic Association (NCAA), primarily competing in the Great Lakes Valley Conference (GLVC) since the 2009–10 academic year, which they became a full-fledged Division II member on August 1, 2010.

The Prairie Stars previously competed in the American Midwest Conference (AMC) of the National Association of Intercollegiate Athletics (NAIA) from 2003–04 to 2008–09.