Crawford H. Greenewalt's personal papers are primarily focused on his retirement years and his avocational interests.

The papers document Greenewalt's political activities in the Republican National Committee, and include exchanges with many of the leading political and business figures of the day. Greenewalt was a member of the Business Council and its predecessors, and was the chairman of its liason groups with the U.S. Interior and Defense departments. Copies of Business Council minutes and correspondence documents the influence of this group on public policy during the 1950s, 1960s, and 1970s. The files include a brief history of the Business Council. The file on Greenewalt's chairmanship of Radio Free Europe (1963-1966) includes a recording of a broadcast interview with ex-president Eisenhower.

Greenewalt's most important corporate directorships were with the Boeing Company (1963-1974) and the Morgan Guaranty Trust Company (1963-1973). The Boeing files include copies of minutes that document the financing of the Boeing 747; publicity for the 727, 737, and 747; the abortive American supersonic transport program; and projects for STOL aircraft and hydrofoils.

Of particular significance are the papers describing Greenewalt's work in photography and ornithology, beginning in 1948. These materials trace his research interests in the hummingbird and bird flight and his trips to places like Brazil, Peru, Venezuela, the Antilles, New Guinea, and the Galapagos Islands in order to observe and photograph birds in their natural habitats. The papers also describe the writing and publication of his hummingbird book, as well as Greenewalt's involvement with the American Museum of Natural History, the Academy of Natural Sciences, the National Academy of Sciences, and the National Geographic Society. The papers include Greenewalt's copies of minutes of committees of the American Philosophical Society, the Smithsonian Institution's Board of Regents (including the establishment of Smithsonian magazine) and the Carnegie Institution of Washington, particularly regarding its plans for a large telescope in the Southern Hemisphere.

Other files describe Greenewalt's work on the visiting committee at MIT (1965-1987), which evaluated the school's academic programs. Similar files on his work with the University of Chicago, particularly its program on nuclear studies, include an essay on Arthur H. Compton and describe the 40th anniversary celebration of the first nuclear chain reaction. Greenewalt's involvement in local affairs includes the Committee on Regional Development, which unsuccessfully sought to consolidate regional port authorities and airports, and the Greater Wilmington Development Council.

Miscellaneous items of interest include a study of the history of DuPont's oval trademark; Greenewalt's opinions on the qualifications for DuPont directors; studies of woodwinds, obesity in women, and Alzheimer's disease; dedication ceremonies for the Greenewalt Laboratory at DuPont's Experimental Station; scrapbooks; honorary degrees; awards; and speeches.