1880 Birth:1207 H. Willis birth date estimated as January 1880 given his age (5 months) in the 1880 census enumeration taken on 1 June 1880; birth place of the Village of Cherokee in Oregon Township, Butte County, California assumed because parents Jacob Patterson and Mary A. McEldowney were enumerated in that location in the 1880 enumeration.

1880 U.S. Census:1207 H. Willis enumerated in the household of his father Jacob Patterson in the Village of Cherokee in Oregon Township, Butte County, California as a white male, 5 months, son, single, at home, born in California, father born in Ohio, mother born in Ohio.