Smithsonian Institution Bureau of American Ethnology Search this
Microfilm and digital surrogates of microfilm are available. See Volume 7, reel 16, which also contains correspondence from the Letters Sent subseries.
Electronic inventory available. Consult with archivist. For a comprehensive description of these materials, see "The papers of John Peabody Harrington in the Smithsonian Institution, 1907-1957, Volume 9: A guide to the correspondence," edited by Louise G. Mills and Elaine L. Mills (1991). http://anthropology.si.edu/naa/harrington/pdf/mf_guides/jp%20harrington%20guide%20-%20volume%209.pdf
The letters have been arranged in alphabetical order according to the name of the writer. There are several items at the end of the set in which the sender is not clearly identified
This subseries of the Correspondence series is a small file of letters sent or received by persons other than Harrington. Some of these items may have been hand delivered to him; others were possibly enclosures which became separated from their covering letters.
Certain letters were sent to and from individuals who were staying with him such as Indian informants (Lucerecia Garcia, Isabelle Meadows, Perry Keahtigh) or young assistants (Jack and Glenn Marr). In some cases Harrington actually wrote the letters and signed the informant's name.
Correspondence, Third person letters, John Peabody Harrington papers, National Anthropological Archives, Smithsonian Institution
National Anthropological Archives, Smithsonian Museum Support Center, Suitland, Maryland