William Harrison Johnston was born 1807 in Westmoreland, Pennsylvania, USA to Thomas Johnston and Nancy Agnes Nelson and died 1891 Van Buren, Indiana, USA of unspecified causes. He married Martha Forbes .
Children
| Name | Birth | Death | Joined with |
| James Johnston | |||
| Nancy Jane Johnston | |||
| John Francis (Frank) Johnston | |||
| Mary Ellen Johnston | |||
| Katherine E. Johnston | |||
| William Marshal Johnston | |||
| Amanda Johnston | |||
| Joseph A. Johnston | |||
| Thomas Johnston | |||
| William Nelson Johnston | |||
| Martha Johnston | |||