The University Libraries currently houses four unique collections.
The digital projects principally shed light on American history and culture, and include the award-winning Lincoln/Net, Mark Twain's Mississippi, and a number of other web sites. Many of these resources are unique in that they complement searchable collections of text, image, and sound materials with original interpretive resources. These include essays and streaming video in which scholars discuss the contexts in which featured primary sources were created.
The libraries also host the Southeast Asia Digital Library, a major international project bringing primary source materials from libraries, museums, and other collections in Southeast Asia to a free-use World Wide Web site.
Rare Books & Special Collections has over 42 specialized collections. Unique among these are Dime Novels, the Lesbian, Gay, Bisexual, & Transgender (LGBT) collection, Science Fiction materials, and comic books. Additionally, RBSC is the official repository of the Horatio Alger Society.
The Donn V. Hart Southeast Asia Collection is one of the best Southeast Asian collections in the country. With specific strengths in the humanities and social sciences, the collection supports a wide variety of scholarly research interests.
In addition to maintaining official records and documents pertaining to the University, the Regional History Center and University Archives houses collections of note such as the DeKalb Ag Research Records, the Chicago and North Western Railway Historical Society Records, and local government records (Illinois Regional Archives Depository).