| 1855 | In November, approximately 50 books arrive from New York sent by Amos Dean, president of the University. They are stored in a room in the Mechanics’ Academy. |
| 1859 | The library is relocated to Central Hall (Old Capitol). |
| 1881 | Ada North, the library’s first professional librarian, introduces the card catalog and in 1886 institutes use of the Dewey Decimal classification system. |
| 1882 | The library moves to the second floor of North Hall. |
| 1884 | The library is designated a U.S. Federal Depository Library. |
| 1897 | A major fire damages North Hall and destroys much of the collection. |
| 1902 | The library moves to the Hall of Liberal Arts (Schaeffer Hall) . |
| 1908 | The library moves again, this time to the Hall of Natural History (Macbride Hall). Over the next 43 years, the general collection grows from 64,286 volumes to more than 600,000. |
| 1927 | The Library Annex is opened in the Old Armory (formerly the Men’s Gymnasium) to house the Reserve Reading Room, Serials Department, and Government Documents. |
| 1937 | The Art Library is established in the new Fine Arts Building. |
| 1949 | Construction begins on the first separate library building in the University’s history. |
| 1950 | Library of Congress call numbers are instituted to replace the Dewey Decimal classification system. |
| 1951 | The new building opens with 137,500 square feet of space. |
| 1961 | The first addition to the new building is completed and then extended in 1965. |
| 1964 | The Friends of the University of Iowa Libraries is organized. An earlier attempt to establish a Friends group had failed in 1944. |
| 1972 | The last major addition to the Main Library is completed, more than doubling its size to 440,000 square feet. |
| 1974 | The Health Sciences Library is completed, allowing the medicine, dentistry, pharmacy, speech pathology and audiology, and nursing collections to finally be combined in one building. In 1989 the library is renamed in honor of Dr. Robert C. Hardin. |
| 1977 | Acquisition of the 2 millionth volume |
| 1979 | Automation is introduced when the Libraries joins the Research Libraries Group (RLG) for cataloging support. |
| 1988 | OASIS, the on-line catalog of library holdings, is implemented. |
| 1989 | Acquisition of the 3 millionth volume |
| 1992 | The Information Arcade, a facility for using electronic information and multimedia, is created with a grant from the Roy J. Carver Charitable Trust. |
| 1992 | The Louise Noun-Mary Louise Smith Iowa Women’s Archives is established to collect and preserve the history of Iowa’s women. |
| 1994 | The Business Library moves to new quarters in the Pappajohn Business Building. In 1997 it is renamed in honor of Marvin A. Pomerantz. |
| 1996 | Based on the success of the Information Arcade, the Information Commons opens in the Hardin Library for the Health Sciences and is expanded in 1999. |
| 1999 | The Biological Sciences Library moves to the renovated Biology Annex building. |
| 2000 | The web-based on-line catalog InfoHawk replaces OASIS. |
| 2001 | The Engineering Library moves into new facilities in the Seamans Center for the Engineering Arts and Sciences. |
| 2005 | The Libraries celebrates its sesquicentennial |
