Mark O. Hatfield Library, Academic library at Willamette University, Salem, United States.

Mark O. Hatfield Library is an academic library at Willamette University in Salem that holds research materials, digital collections, and archives across multiple floors. The spaces are organized to give students and researchers access to books, journals, and electronic resources.

Willamette's library began in 1844, two years after the university's founding, and was first kept on the third floor of University Hall (now Waller Hall). A fire gutted that building on December 17, 1919; the library reopened on its second floor in December 1920. In 1938 it moved into a concrete and brick building designed by Pietro Belluschi, now Smullin Hall. The Hatfield building, funded by over 1,300 private donors at a cost of $7.4 million, was dedicated on September 4, 1986.

The library is named for Mark O. Hatfield, a 1943 Willamette graduate and former faculty member who later served as Oregon governor and U.S. senator. Its archives department received a $500,000 grant from the Meyer Memorial Trust in 2002. In 1999 a vandal cut the 30 pages out of a rare copy of The Old Days in and Near Salem, Oregon; the Oregon State Library donated a replacement.

The main entrance sits near the northwest corner, where a glass-enclosed stairwell juts out from the rectangular brick block; the north and south faces are clear glass, the other two orange brick. Inside are a 24-hour study area, private study rooms, a classroom, listening rooms and the university archives. The Mill Race flows along the north side, next to Glenn Jackson Plaza.

The Fish Bowl is a 24-hour study area that gives students access to learning spaces at any time, regardless of regular hours. This space was designed to help students who want to work at night or at unusual times.