| 1840 FERGUSON Index | ||||
| Last | First | Census | Location | Census |
| Name | Name | State | (County; Town) | Year |
| Ferguson | Hugh | IL | Adams; no twp listed | 1840 |
| Fergason | Joseph | IL | Adams; no twp listed | 1840 |
| Furgurson | Allen | IL | Adams; Quincy | 1840 |
| Furgusson | Henry | IL | Adams; Quincy | 1840 |
| Furguson | Isaac | IL | Adams; Quincy | 1840 |
| Furguson | Samuel | IL | Adams; Quincy | 1840 |
| Furguson | Samuel | IL | Adams; Quincy | 1840 |
| Ferguson | Danl | IL | Bond; no twp listed | 1840 |
| Ferguson | Marshall | IL | Cass; no twp listed | 1840 |
| Ferguson | Wm | IL | Cass; no twp listed | 1840 |
| Fergusson | James | IL | Christian; no twp listed | 1840 |
| Fergusson | Philip C | IL | Christian; no twp listed | 1840 |
| Furgusson | William H | IL | Christian; no twp listed | 1840 |
| Forgason | Jas | IL | Clark; no twp listed | 1840 |
| Fargason | Robert | IL | Clark; no twp listed | 1840 |
| Ferguson | Stephen | IL | Coles; no twp listed | 1840 |
| Ferguson | Wm | IL | Coles; no twp listed | 1840 |
| Furgeson | Gilbert | IL | Cook; Des Plains | 1840 |
| Fergeson | S | IL | Cook; Monroe | 1840 |
| Furgerson | Alex | IL | Fayette; no twp listed | 1840 |
| Furguson | James | IL | Gallatin; Monroe | 1840 |
| Furguson | James | IL | Gallatin; Monroe | 1840 |
| Furguson | James | IL | Greene; Apple Creek | 1840 |
| Furguson | John | IL | Greene; Apple Creek | 1840 |
| Furguson | Berry | IL | Greene; Carrollton | 1840 |
| Furguson | James | IL | Greene; Carrollton | 1840 |
| Furguson | Anderson | IL | Greene; Mount Airy | 1840 |
| Forgison | Richard | IL | Greene; Wilmington | 1840 |
| Fergusson | A | IL | Jasper; no twp listed | 1840 |
| Fergusson | Henry | IL | Jasper; no twp listed | 1840 |
| Fergusson | Sarah | IL | Jasper; no twp listed | 1840 |
| Furgeson | Thomas | IL | Jasper; no twp listed | 1840 |
| Furguson | George | IL | Jo Daviess; Galena | 1840 |
| Farguson | Rice | IL | Jo Daviess; Plum River | 1840 |
| Ferguson | William | IL | Kane; no twp listed | 1840 |
| Furgason | Jacob | IL | Knox; Hendersonville | 1840 |
| Furgason | Alexander | IL | Knox; no twp listed | 1840 |
| Furgason | James | IL | Knox; no twp listed | 1840 |
| Ferguson | Bartly | IL | La Salle; no twp listed | 1840 |
| Ferguson | John | IL | La Salle; no twp listed | 1840 |
| Furgerson | Geo | IL | Lawrence; no twp listed | 1840 |
| Ferguson | Henry J | IL | Macoupin; no twp listed | 1840 |
| Furgerson | Isaac | IL | Madison; Marine | 1840 |
| Furgerson | J L | IL | Madison; Marine | 1840 |
| Ferguson | A | IL | Madison; Monticello | 1840 |
| Ferguson | Thomas | IL | Madison; Omph Gent | 1840 |
| Ferguson | Lawrince | IL | Madison; Ridge Prairie | 1840 |
| Ferguson | Chloe | IL | Madison; Six Mile | 1840 |
| Ferguson | Cumberland | IL | Madison; Upper Alton | 1840 |
| Ferguson | Elish | IL | Mcdonough; no twp listed | 1840 |
| Furguson | John | IL | Mcdonough; no twp listed | 1840 |
| Furguson | William | IL | Mcdonough; no twp listed | 1840 |
| Ferguson | Alex | IL | Menard; no twp listed | 1840 |
| Fergusson | Ferdinand | IL | Menard; no twp listed | 1840 |
| Fergusson | G W | IL | Menard; no twp listed | 1840 |
| Ferguson | George | IL | Menard; no twp listed | 1840 |
| Ferguson | James D | IL | Menard; no twp listed | 1840 |
| Fergerson | Lewis | IL | Menard; no twp listed | 1840 |
| Ferguson | Lewis | IL | Menard; no twp listed | 1840 |
| Ferguson | Lewis | IL | Menard; no twp listed | 1840 |
| Furgeson | Benjamin | IL | Morgan; no twp listed | 1840 |
| Furguson | John P | IL | Morgan; no twp listed | 1840 |
| Furguson | Athol | IL | Ogle; Washington Precinct | 1840 |
| Ferguson | Margaret | IL | Perry; no twp listed | 1840 |
| Ferguson | Henry | IL | Pike; no twp listed | 1840 |
| Ferguson | J H | IL | Pike; no twp listed | 1840 |
| Ferguson | William | IL | Pike; no twp listed | 1840 |
| Ferguson | Marmeduke | IL | Randolph; no twp listed | 1840 |
| Ferguson | Morgn | IL | Rock Island; no twp listed | 1840 |
| Furgason | Andrew | IL | Saint Clair; no twp listed | 1840 |
| Ferguson | Howard | IL | Saint Clair; no twp listed | 1840 |
| Furgeson | Robert | IL | Saint Clair; no twp listed | 1840 |
| Fergason | Benja | IL | Sangamon; Springfield | 1840 |
| Forguson | Aaron | IL | Shelby; no twp listed | 1840 |
| Forguson | John | IL | Shelby; no twp listed | 1840 |
| Ferguson | Lard H | IL | Union; no twp listed | 1840 |
| Ferguson | Margaret | IL | Union; no twp listed | 1840 |
| Ferguson | Henry | IL | Vermilion; no twp listed | 1840 |
| Furgason | John | IL | Washington; no twp listed | 1840 |
| Furgason | Thomas | IL | Washington; no twp listed | 1840 |
| Furgeson | Wm | IL | Will; Lockport Precinct | 1840 |
| Ferguson | Duncam | IL | Winnebago; no twp listed | 1840 |
| Ferguson | William | IL | Winnebago; no twp listed | 1840 |