The Frederick C. Belen papers contain photographs related to Belen's career. Images include scenes of Belen with people and groups, including giving speeches, presenting gifts to dignitaries, and on tours. There are also photographs of groups without Belen, and of Belen's office. There are photographs of Dwight D. Eisenhower, Hubert Humphrey, Lyndon B. Johnson, John F. Kennedy and W. Marvin Watson. Other images include mail trucks with logos on them about the new use of ZIP codes.

The correspondence includes letters and cards from well-known politicians such as G. Mennen Williams, Ted Kennedy, Hubert Humphrey, Robert Byrd, Franklin D. Roosevelt Jr., J. Edgar Hoover, Ronald Reagan, and Robert Kennedy. Materials from Belen's service during World War II include personal history, promotion letters, pay, leave, and his orders. The "Personal" folder consists of a variety of materials, such as correspondence from relatives and colleagues, reports from the U.S. House of Representatives Committee on Un-American Activities, Shipley Terrace Citizens Association bylaws and constitutions, Veterans Administration correspondence, and Belen's law school grades.

Please note that the folder titles are the same used by the creator. The archivist provided fuller forms of names, rather than the abbreviations provided by Belen.