The Washingtoniana Ephemera Collection contains rare historical materials written or printed on paper.

The collection includes handwritten letters, programs, meeting minutes, speeches, tickets, brochures, pamphlets, invitations, deeds, building specifications, financial records, legislative materials, and political memorabilia. Of significance are items concerning 19th century mayors and other elected officials, records of numerous civic and social organizations, early records about D.C. parks and land development, church and school programs, D.C. militia memorabilia, and autographs of famous persons. Ephemera Collection materials were formerly part of the Washingtoniana vertical files and were separated into a new collection to ensure their preservation.