- R. H. Logan Papers, 1895/18991
- Racial and Ethnic Ephemera Collection, 1778/20051
- Randolph Lytton historic Washington, D.C. postcards and photographs collection, 1905/19681
- Reed Family Papers
1899-19461
- Reed Family Papers, 1899/1946, bulk 1910/19461
- Rev. Samuel Huntting Sayre, Jr. Papers, 1874/1989, bulk 1920/19601
- Roane Family Papers, 1880/1973, bulk 19501
- Robert A. Lewis papers, 1938/19441
- Robert Edward Minshall Papers, 1909/19431
- Robert Truax Washington, D.C. transportation collection, 1880/19851
- Russell Family Correspondence, 1927/19431
- Ryland Correspondence Collection, 1843/19881