1900 Census
Ferguson        Mary             28  Female  Norw    SD      Codington 2-Wd Watertown
Ferguson        William H        31  Male    Wi      SD      Codington Elmira Twp
Fergenson       George           24  Male    Ny      SD      Codington Henry Twp
1920 Census
Ferguson        Alexander        36  Male    Ia      SD      Codington 2-Wd; Watertown