William and Janet (likely father and daughter) arrived in New York on 6 July 1866 via the Arkwright. "W. Mitchell" appears on overland company records with a notation that he purchased 2 adult food rations, indicating Janet was still with him. PEF records also indicate that the traveling group consisted of two individuals. Further research is needed to identify exactly who these two people were.
His birth year is extrapolated from his age given on ship records.