| Father | Richard UNDERWOOD Jnr (1852 - 1935) |
| Mother | Jane Catherine "Jenny" WILLIAMSON (1861 - 1916) |
| Sibling | Jane Rose UNDERWOOD (1883 - 1961) |
| Sibling | Richard James UNDERWOOD (1885 - 1952) |
| Sibling | Thomas Kerr UNDERWOOD (1887 - 1962) |
| Sibling | Robert Francis UNDERWOOD (1889 - 1934) |
| Sibling | William Stanley UNDERWOOD (1892 - 1962) |
| Sibling | Gertrude May UNDERWOOD (1895 - 1974) |
| Sibling | John Avenel UNDERWOOD (1897 - 1897) |
| Sibling | Ellen Jane "Nell" UNDERWOOD (1899 - 1977) |
| Sibling | Olive Isabella UNDERWOOD (1903 - 1966) |
| Sibling | Roderick Williamson UNDERWOOD (1907 - 1956) |