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Mary Mccormick — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Dekalb-County, Illinois
Our Model Tree links this Mary Mccormick across the 1930 and 1940 US Censuses in Dekalb-County, Illinois (XGBoost, ~Confirmed) — first a spouse (b.~1899), then head of a 11-person household.
Age 41
b. ~1899
Female
Spouse
Born: Illinois
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Dekalb-County, Illinois |
| Surname | McCormick |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 41 |
| Marital Status | Married |
| Birthplace | Illinois |
| 1935 Residence (City) | De Kalb twp |
| 1935 Residence (County) | De Kalb |
| Additional Details | |
| Income (1939) | 0 |
| Highest Grade | H 1 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Township / Ward | De Kalb Twp |
| Est. Birth Year | ~1899 |
Household Members
Census records only state relationship to the household head.
Pairwise kinship is derived (~90–95% accurate), not recorded.
Step/blended families and boarders can break it.
11 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Catherine Mccormick | Daughter | — | 17 | ~1923 |
| Helen Mccormick | Daughter | — | 5 | ~1935 |
| Rosann Mccormick | Daughter | — | 8 | ~1932 |
| John Mccormick | Head | — | 42 | ~1898 |
| Patrick Mccormick | Son | — | 1 | ~1939 |
| Robert Mccormick | Son | — | 19 | ~1921 |
| Donald Mccormick | Son | — | 10 | ~1930 |
| John Mccormick | Son | — | 21 | ~1919 |
| Malachi Mccormick | Son | — | 3 | ~1937 |
| Bernard Mccormick | Son | — | 12 | ~1928 |
| Mary Mccormick | Spouse | — | 41 | ~1899 |
Census Appearances
1930
Dekalb, Illinois
Other, age 31
Dekalb, Illinois · implied b. ~1899 — 19 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McCormick |
| Given Name | Mary S. |
| Relationship to Head | Wife-H |
| Sex | F |
| Color / Race | White |
| Age | 31 |
| Marital Status | Married |
| Birthplace | Illinois |
| Age at First Marriage | 19 |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Illinois |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Dekalb-County, Illinois
Spouse, age 41
Dekalb-County, Illinois · implied b. ~1899 — 11 household members
| Surname | McCormick |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 41 |
| Marital Status | Married |
| Birthplace | Illinois |
| 1935 Residence (City) | De Kalb twp |
| 1935 Residence (County) | De Kalb |
| Income (1939) | 0 |
| Highest Grade | H 1 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
Model Tree
An inferred pedigree reconstructed from census links — up to 4 generations within the 1900–1950 window. Closer generations are built from household co-residence; deeper ones are bridged by following a relative to their own childhood census. Confidence compounds and weakens with each generation.
Our Model Tree links Mary Mccormick across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
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This person
Anchor record
Mary Mccormick
Spouse · 1940 · age 41 · b. ~1899 · Illinois
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Confirmed / household (~0.90+)
Probable / derived (~0.65–0.89)
Candidate (<0.65, unverified)
Original Census Page
1940 US Federal Census — Dekalb-County, Illinois
Open full size
1940 US Federal Census — Dekalb-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00793-00504)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Rodger | 5 | Son | — | Illinois |
| 2 | John D Mccormick | 42 | Head | Labour | Illinois |
| 3 | Ruth Mccormick | 19 | Wife | — | Illinois |
| 4 | John B Mccormick | 42 | Head | Farmer | Illinois |
| 5 | Mary Mccormick THIS PERSON | 41 | Wife | — | Illinois |
| 6 | John Jr. Mccormick | 21 | Son | Bookkeeper | Illinois |
| 7 | Robert Mccormick | 19 | Son | — | Illinois |
| 8 | Catherine Mccormick | 17 | Daughter | — | Illinois |
| 9 | Bernard Mccormick | 12 | Son | — | Illinois |
| 10 | Donald Mccormick | 10 | Son | — | Illinois |
| 11 | Rosann Mccormick | 8 | Daughter | — | Illinois |
| 12 | Helen Jean Mccormick | 5 | Daughter | — | Illinois |
| 13 | Malachi Mccormick | 3 | Son | — | Illinois |
| 14 | Patrick Mccormick | 1 | Son | — | Illinois |
| 15 | Everett Davis | 27 | Head | Labourer | Illinois |
| 16 | Hattie B Davis | 26 | Wife | — | Illinois |
| 17 | Donna Kay Davis | 2 | Daughter | — | Illinois |
| 18 | Burl Kern | 20 | Brother-in-law | Labourer | Illinois |
| 19 | Mabel Kern | 18 | Sister-in-law | — | Illinois |
| 20 | Charley Davis | 57 | Father | — | Illinois |
| 21 | Nelly Davis | 47 | Mother | — | Illinois |
| 22 | Gene Davis | 13 | Brother | — | Illinois |
| 23 | Davis | None | — | — | — |
| 24 | Fred D Diedrich | 51 | Head | Farmer | Iowa |
| 25 | Clara Diedrich | 49 | Wife | — | Iowa |
| 26 | Mary Margaret Diedrich | 22 | Daughter | Clerk | Illinois |
| 27 | Lucas Diedrich | 20 | Son | Department Store Manager | Illinois |
| 28 | Robert Diedrich | 17 | Son | — | Illinois |
| 29 | John Diedrich | 14 | Son | — | Illinois |
| 30 | Eva Elizabeth Diedrich | 12 | Daughter | — | Illinois |
| 31 | Arthur Diedrich | 12 | Son | — | Illinois |
| 32 | Erest F. Jordan | 45 | Head | — | Illinois |
| 33 | Evelyn Jordan | 48 | Wife | — | Iowa |
| 34 | Joseph Jordan | 14 | Son | — | Illinois |
| 35 | Mary Jordan | 10 | Daughter | — | Illinois |
| 36 | Margaret Ann Jordan | 9 | Daughter | — | Illinois |
| 37 | Catherine Jordan | 8 | Daughter | — | Illinois |
| 38 | Charles O Williams | 54 | Head | Farmer | Kentucky |
| 39 | Iona Williams | 53 | Wife | — | Kentucky |
| 40 | Velma Williams | 26 | Daughter | Clerk | Illinois |
About This Record & Model Tree
This record was independently indexed by YourRoots from the 1940 United States Federal Census (NARA). Our Model Tree links this person across census decades using XGBoost-based record linkage, with per-link confidence scores. Household corroboration strengthens the signal when co-residents appear on the same census pages in multiple years.
Source: National Archives and Records Administration (NARA)