Henry Castillou was a Canadian pack train operator, lawyer, judge, legal advisor, and hobby anthropologist in British Columbia, known for his legal advocacy for First Nations communities. Castillou was born in Coldwater Valley near Merritt on May 25, 1896, where he quickly became involved in the operations of a pack train by the age of sixteen. After serving in the Royal Flying corps in World War I, Castillou went on to attend law school and began practicing law in Vancouver in 1923. His legal career involved many defence cases and Castillou became known for advocating for Indigenous rights, especially in his role as a legal advisor to the North American Indian Brotherhood. By 1950 he was appointed as a judge in the Cariboo, after previously acting as a government agent in an investigation of an opium drug ring while continuing his other legal activities. During his spare time, Castillou was interested in the history of First Nations in B.C. and collected artifacts to add to his expansive collection of implements, basketry, and belongings. After retiring from his professional life in 1960, Castillou passed away in 1967 at the age of 71.