A ballpark at the site was the Cubs' home from 1893 to 1915 before they moved to Wrigley Field.
The Way Out in Left Field Society says the plaque recognizes an important site in Chicago baseball history.
Former Cubs' ballpark dedicated over weekend
Saturday's dedication program included music and "Mr. Cub," former home run slugger Ernie Banks, who came to the University of Illinois Medical Center to memorialize the West Side grounds. That's where, in 1906, the Cubs hosted the White Sox in Chicago's first Crosstown series.
