James H. McMillen (1823-1913) was an Oregon pioneer of 1845, volunteer in the Cayuse Indian war, and resident of Washington County, Oregon. Collection consists of McMillen's manuscript reminiscences, 1910-1911, in the form of a letter to George Himes, regarding his journey to Oregon in 1845; his acquaintance with John McLoughlin and Peter Skene Ogden; and his recollections of the Whitman killings, Cayuse Indian War, and early Portland, Oregon.