The Vertical Files collection is an artificial collection of materials on various topics, individuals, and organizations, both Irish-American and Irish. The collection includes contracts, constitutions, flyers, broadsides, leaflets, clippings, reports, pamphlets, catalogs, brochures, bibliographies, press releases, programs, posters, sheet music, audiovisual materials, some born-digital materials, and other printed ephemera.

The bulk of this collection represents the type of literature that has commonly circulated within the New York Irish community since 1970. Information on more than 100 non-profit Irish American political and cultural organizations and events, businesses, the Irish language, one-time events such as demonstrations and poetry readings, and individuals is included. Also included are clippings and articles on famous Irish-Americans, gift catalogs, and information relating to publications. Some of the more documented institutions and topics covered are the Emerald Isle Immigration Center, the Glucksman Ireland House, the Irish American Cultural Institute, Irish Books and Media, Inc., The Irish Repertory Theatre, Saint Patrick's Day Parade organizations and events, and theater productions on and off Broadway. The majority of materials date from the 1970s and on.