- Record Unit 60, Meteorological Project, Records, 1849–1875
Most of these records are requests for weather data, or requests from researchers interested in the correspondence of an observer who worked on Secretary Joseph Henry’s Smithsonian Meteorological Project.
- Record Unit 70, Exposition Records of the Smithsonian Institution and United States National Museum, 1867–1940
This is the primary record of the Smithsonian's involvement in World's Fairs, however, substantial records are also found in Record Unit 192. Photographs from expositions are found in Record Unit 95. There are also resources at other Smithsonian repositories relating to expositions—the largest being a collection of catalogs and other literature at the Smithsonian Institution Libraries. Library, and other material can be found in the Smithsonian Collections Search.
- National Zoological Park Records. Researchers can conduct focused searches on records from the National Zoological Park in the Archives' Collection Search. Of special note is Record Unit 74, National Zoological Park, Records, 1887–1966. This large record unit is a central file documenting the first seventy-five years of the zoo's history.
- Record Units 311 and 312, Director, National Collection of Fine Arts, 1892–1965. These records pertain to the National Collection of Fine Arts, which was later renamed the National Museum of American Art, and is now named the Smithsonian American Art Museum. They are the best source of information on early art exhibitions at the Smithsonian.
- Record Unit 321, Office of Program Support, National Museum of American Art, 1947–1981. These records are primary documentation of the United States’ art exhibitions abroad program after World War II. Researchers can conduct focused searches on records from the Smithsonian American Art Museum in the Archives' Collection Search.