- IAWA Small Collections, 1907/20134
- IAWA: International Archive of Women in Architecture Records, 1967/2013, bulk 1985/20081
- Ignorance Club collection, 1908/20242
- Independent Order of Odd Fellows. St. Albans Lodge, No. 31 (St. Albans, Vt.) Minute Book, 1917/19322
- Independent Order of St. Luke Records, 1877/19706
- Index to Topographic Maps and Geologic Folios, Virginia, 19181
- Inge Horton Architectural Collection, 1964/1999109
- Institute for the History of Technology and Industrial Archaeology Records, 1875/2005, bulk 1980/200534
- Institute for the History of Technology and Industrial Archaeology, Records regarding Blair Mountain, 1906/1992, bulk 1990/19921
- Instructive Visiting Nurses Association records, 1902/199910
- Internal Library Records, 1923/20231
- International Association for Identification Records, 1842/2012, bulk 1910/195951
- International Order of Odd Fellows, Lodge 134, Ledgers, 1892/19281
- Ira E. Robinson Papers, 1818/19301
- Ira E. Robinson Papers, 1869/19511