It was founded in January 1833 at Palace Green by a 160 volume donation by the then Bishop of Durham, William Van Mildert, and now holds over 1.6 million printed items.

The building was built in 1667–69 by the Quaker architect John Langstaffe specifically to house Cosin's collection of over 5,000 books.

[5] Cosin's Library is a Grade II* listed building and an ancient monument, and is located inside the Durham Castle and Cathedral UNESCO World Heritage Site.

The original portrait panels located above the bookshelves were painted by Jan Baptist van Eerssell in 1668–1669.

Nearly three hundred years later, a former university librarian, David Ramage, completed Cosin's original plan for the library by painting further portrait panels for the smaller room added in 1670–1671.

However, after it received Martin Routh's library in 1855 this space proved insufficient and it expanded into the upper floor of the Exchequer Building next door.

An 1857 Ordnance Survey map shows two of the stables – one on Palace Green and one behind the Diocesan Registry (built 1822; now the Music Library building) had been converted into lecture rooms.

In 1882, the stable block fronting onto Palace Green between Cosin's Library and the diocesan registry was demolished and replaced with a new two-storey perpendicular Tudor building by Sir Arthur Blomfield with two large lecture rooms – now the University Library building.

These were identified as Scottish soldiers captured by Oliver Cromwell at the Battle of Dunbar in 1650 and subsequently imprisoned in Durham Cathedral.

[19][20][21][22][23][24] In 2014, the university's Museum of Archaeology (originally established in 1833) moved into a new gallery in Palace Green Library, open for free to the public.

[30][31][32] In 2023, the library joined the SafePod Network,[33] giving secure data access from a 'pod' installed in the Bill Bryson Library to sensitive datasets from the Office for National Statistics, the UK Data Service, the Health and Care Research Wales-funded Secure Anonymised Information Linkage Databank, the Scottish Government, and Health and Social Care Northern Ireland's Honest Broker Service.

[61] As well as the libraries, there are 450 study spaces in the Lower Mountjoy Teaching and Learning Centre, as well as a study hub in Durham University Business School (only accessible by students at the business school) that includes a reference collection of core texts.

[61] There are also additional study spaces (not considered library locations) in Elvet Riverside, the Mathematical Sciences and Computer Sciences Building (Upper Mountjoy), Dunelm House (students' union) and the Calman Learning Centre (Lower Mountjoy).

[63] The Bill Bryson Library (known informally as the "Billy B"), on the university's Lower Mountjoy campus, was built in three stages between the 1960s and 1990s, when the west wing was added.

[71] The library also occupies various other buildings on the site, including former stables and a coach house from before the university took occupation, and infill extensions from the 20th and 21st centuries.

[77] In 2019 a visiting fellow at the residential research library from the University of Bristol found a royal charter of King John from 1200 in the archives of Ushaw College.

[82] There are also Spanish Gallery Collection Research Fellowships, funded by the Centro de Estudios Europa Hispánica, which are offered jointly with the university's Zurbarán Centre in Bishop Auckland and are for research into the collection of the Spanish Gallery in Bishop Auckland.