The legal advocacy work of the ACLU-NC is represented in over 1,000 case files, dated between 1934 and 1974. Arranged alphabetically by the client’s last name, these files contain correspondence, legal documents, and attorneys’ working notes for a broad range of civil liberties cases in California. ACLU-NC files for cases argued before the United States Supreme Court are found throughout the series and include, notably, the Frank Conner due process case (1939-1941); the Korematsu and Endo cases, which challenged the constitutionality of Executive Order 9066 (1942-1946); the Louis Hartman loyalty/security case (1958-1963); and the free speech cases of William Ehlert and Edmund di Tullio (1964-1971). Other notable clients whose cases are represented in the collection include Warren Billings, Harry Bridges, Angela Davis, Fred Edwards, and Anita Whitney.

Thirty-one boxes of unprocessed case files, dated between 1971 and 1989, were added to the collection in 2011. They were procesed in 2019, and organized by name of case, including both the names of the plaintiffs and the defendants, and the dates during which the cases took place.