The Project Files series contains the records of twelve of the ACLU's projects, which each addressed an area of civil liberties violations. Project records typically consist of case files, research files, and project publicity and correspondence. The best documented projects are the Children's Rights Project and Women's Rights Project, and to a lesser extent the Arts Censorship Project, Capital Punishment Project, and Reproductive Freedom Project.

The Regional Offices series documents the work and administration of the ACLU's three regional offices: Mountain States Regional Office, concerned with civil rights in the west and Native American rights, the Southern Regional Office, focusing on civil rights in the south, and the Washington, D.C. office, which concentrates on national legislation and the actions of the federal government. The files include correspondence, case files, office publications, research files, and the papers of individual staff members. Subgroup 3, Subseries 5B (Southern Regional Office) has been digitized and is available for members of the Princeton community to view here. To view the database from outside Princeton University, please see the Guide to the American Civil Liberties Union Records.

The ACLU is the preeminent civil liberties organization in the United States. These records document the work of their national office in the areas of civil rights, children and women's rights, freedom of speech (and all First Amendment questions), and due process, among many others, predominantly from 1970 to 2000.

Ananda K. Coomaraswamy was a noted art historian and champion of Ceylonese and Indian culture. This collection covers a broad spectrum of Ananda K. Coomaraswamy's work in the fields of art history, philosophy, religion, and social criticism.

Consists of the correspondence of Russian poet, translator, and writer Anatoly Naiman (1936-2022) along with some writings, photographs, personal documents, and clippings. Other individuals represented in the collection include Anna Ahkamatova, Joseph Brodsky, Sergei Dovlatov, Lidia Chukovskaya, Evgenii Rein, and Dmitrii Bobyshev.

The Papers of Andrew C. Imbrie, Class of 1895, (1875-1965) provide information on his undergraduate years, his service as an alumni trustee from 1907 until 1912 (including a period as Financial Secretary of the Princeton University Board of Trustees (1909-1912) during which he had charge of reorganization of the business management of the University leading to the creation of what became the Office of the Controller) and his family's genealogy.

Consists of an open collection of photographs by Angelos Prokopiou.

Consists of miscellaneous papers of George M. L. La Branche relating to angling.

Anne Martindell was one of the first three women to serve in the New Jersey State Senate. After her four-year term ended in 1977, she served as director of the Office for Foreign Disaster Assistance, and was ambassador to New Zealand and Western Samoa for a two-year term. The papers document her career in politics and civil service, and also contain her unpublished memoirs and personal papers.

Consists chiefly of correspondence between artist Annette Covington and Princeton professor and dean Luther P. Eisenhart, and papers relating to the "Baconian" theory of the authorship of Shakespeare's plays.