| Forthmann, Anna Catharina | 1885 | Grohn | |
| Forthmann, Anna Magdalene Christine | Vossmeyer | 1912 | Bremen 1 |
| Forthmann, Betha Sophie | 1889 | Grohn | |
| Forthmann, Carl Friedrich | 1900 | Lesum | |
| Forthmann, Johann Christian Hermann | Kunst | 1894 | Bremen |
| Forthmann, Johann Heinrich | Kunst | 1889 | Bremen |
| Forthmann, Johann Heinrich | 1886 | Grohn | |
| Forthmann, Metta | 1883 | Grohn | |
| Forthmann, Siegfried Johann | 1894 | Grohn | |
| Forthmann, Sophie Friderike | 1888 | Grohn | |
| Forthmann, Walter Hermann Christian | Kunst | 1891 | Bremen |
| Forthmann, Wilhelmine Johanne | 1882 | Grohn |