The Carnegie Library in Joliet, Illnois
"Today, the main body of the collection -- which includes over 300,000 books and 400 magazine subscriptions -- is housed in the historical 1903 Daniel H. Burnham-designed building in the heart of Joliet City Center. ... In 1991, architects skillfully blended old with new to add on a 49,000 square-foot addition that more than doubled the size of the Library that now takes up half a city block." Information from Joliet library. Status: remains in use as city library.