The largest U.S. academic research libraries
The biggest university libraries in the country hold collections that rival national libraries. The ranking below is by volumes held — the classic measure of a research library — drawn from Association of Research Libraries statistics. These are overwhelmingly the libraries of large doctoral and land-grant universities, where graduate research drives decades of collecting.
By volumes held
| # | University library | Volumes held |
|---|---|---|
| 1 | Harvard University | 20,367,538 |
| 2 | University of Illinois, Urbana-Champaign | 14,297,276 |
| 3 | University of Michigan | 13,829,825 |
| 4 | Yale University | 13,796,100 |
| 5 | Columbia University | 13,305,873 |
| 6 | University of California, Berkeley | 12,674,985 |
| 7 | University of California, Los Angeles | 12,153,191 |
| 8 | University of Texas at Austin | 11,474,528 |
| 9 | University of Chicago | 11,012,065 |
| 10 | Princeton University | 10,159,715 |
| 11 | Indiana University Bloomington | 10,121,934 |
| 12 | University of Washington | 9,761,357 |
| 13 | University of Wisconsin–Madison | 9,535,953 |
| 14 | Ohio State University | 9,471,622 |
| 15 | Cornell University | 9,300,186 |
| 16 | University of North Carolina at Chapel Hill | 8,217,694 |
| 17 | Pennsylvania State University | 7,966,867 |
| 18 | University of Minnesota | 7,781,968 |
| 19 | Duke University | 7,719,701 |
| 20 | University of Colorado Boulder | 7,630,969 |
| 21 | University of Iowa | 7,626,022 |
What “research library” means
Most of these institutions belong to the Association of Research Libraries (ARL), a group of roughly 125 of the largest research libraries in the U.S. and Canada. ARL membership is a useful signal for a student heading into research-intensive study or graduate school: it indicates deep collections, specialized subject librarians, and strong interlibrary networks. For most undergraduates, though, the service and access points on the how-to-judge page matter more than raw size.