| 1840 FERGUSON Index | ||||
| Last | First | Census | Location | Census |
| Name | Name | State | (County; Town) | Year |
| Ferguson | Mary | CT | Fairfield; no twp listed | 1840 |
| Ferguson | Nathaniel | CT | Fairfield; no twp listed | 1840 |
| Furguson | Samuel B | CT | Fairfield; no twp listed | 1840 |
| Ferguson | Daniel | CT | Fairfield; Norwalk | 1840 |
| Furguson | David | CT | Fairfield; Ridgefield | 1840 |
| Furgerson | Wm | CT | Fairfield; Ridgefield | 1840 |
| Furgerson | John P | CT | Hartford; Enfield | 1840 |