The Clifford M. Holland Papers consist mainly of material documenting his career as a tunnel engineer, specifically regarding the construction of tunnels, tunnel linings, shields, design, stress analysis, contracts and bids for work on the Rapid Transit Commission tunnels under the East River in New York City, New York . The bulk of the collection spans the years 1901-1924 and includes correspondence, blueprints, drawings, data sheets and analyses, notebooks, contracts, speeches, clippings and publications. A small amount of material dated 1893 and concerning the East River tunnels may have been from the files of his predecessor.