This series consists of original and reproduced contemporary materials regarding the Whitman killings and their aftermath. The photostatic reproductions of records from the trial and execution of five Cayuse men for the killings were donated to the Oregon Historical Society in 1947; the typescript of Oregon American and Evangelical Unionist articles, which was made in 1917, was acquired either from T. C. Elliott or his estate in 1947 or earlier; the exact provenance of other materials in this series is unknown.