The Holgate family arrived in New York on 23 June 1864 via the ship The General McClellan. William's wife, Martha, died shortly before the ship left Liverpool, and his infant son, Seth, died on the ship.
Only William Sr., Hannah, and John are seen on the Warren Company roster. It is likely that William Jr. hired out as a teamster to help pay passage, but further research is needed to confirm that and which company he hired out for.
Daughter, Mary, is also not seen beyond the ship records. It is assumed that she died prior to the overland journey.