MC
Mary Clark — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Mary Clark across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a spouse (b.~1883), then head of a 5-person household.
Age 57
b. ~1883
Female
Spouse
Born: Ireland
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Clark |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 57 |
| Marital Status | Married |
| Birthplace | Ireland |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Additional Details | |
| Hours Worked | 0 |
| Highest Grade | H-4 |
| 1935 Residence | Same House |
| Birth Country | Ireland |
| Birthplace (normalized) | ireland |
| Township / Ward | Chicago |
| Est. Birth Year | ~1883 |
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.
5 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Rita Clark | Daughter | — | 22 | ~1918 |
| Irene Clark | Daughter | — | 25 | ~1915 |
| Albert Clark | Head | — | 61 | ~1879 |
| John Clark | Son | — | 21 | ~1919 |
| Mary Clark | Spouse | — | 57 | ~1883 |
Census Appearances
1920
Cook, Illinois
Other, age 35
Cook, Illinois · implied b. ~1885 — 14 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Clarke |
| Given Name | Mary |
| Relationship to Head | Employee |
| Sex | F |
| Color / Race | White |
| Age | 35 |
| Marital Status | Single |
| Birthplace | Ireland |
| Year of Immigration | 1908 |
| Naturalization Status | Naturalized |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Occupation | Laundress |
| Industry | Hotel |
| Class of Worker | W |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Mother Tongue | English |
| Birth Country | Ireland |
| Year of Naturalization | 1913 |
| Birthplace (normalized) | ireland |
1930
Cook, Illinois
Other, age 46
Cook, Illinois · implied b. ~1884 — 9 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Clarke |
| Given Name | Mary |
| Relationship to Head | Sister |
| Sex | F |
| Color / Race | White |
| Age | 46 |
| Marital Status | Single |
| Birthplace | Ireland |
| Naturalization Status | Naturalized |
| Year of Immigration | 1907 |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Occupation | Housekeeper |
| Industry | Hotel |
| Class of Worker | W |
| Can Read/Write | Yes |
| Mother Tongue | English |
| Birth Country | Ireland |
| Birthplace (normalized) | ireland |
1940
Cook-County, Illinois
Spouse, age 57
Cook-County, Illinois · implied b. ~1883 — 5 household members
| Surname | Clark |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 57 |
| Marital Status | Married |
| Birthplace | Ireland |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Hours Worked | 0 |
| Highest Grade | H-4 |
| 1935 Residence | Same House |
| Birth Country | Ireland |
| Birthplace (normalized) | ireland |
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 Clark across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage.
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This person
Anchor record
Mary Clark
Spouse · 1940 · age 57 · b. ~1883 · 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 — Cook-County, Illinois
Open full size
1940 US Federal Census — Cook-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00950-00725)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Mary Sullivan | 24 | Daughter | Clerk | Illinois |
| 42 | Martin J. Sullivan | 16 | Son | — | Illinois |
| 43 | Edward Devoy | 31 | Head | Clerk | Illinois |
| 44 | Ann Devoy | 28 | Wife | — | Illinois |
| 45 | Agnes Ann Devoy | 1 | Daughter | — | Illinois |
| 46 | Patricia L. Devoy | 0 | Daughter | — | Illinois |
| 47 | Ella Devoy | 71 | Mother-in-law | — | Illinois |
| 48 | John Staud | 23 | Head | Shipping Clerk | Illinois |
| 49 | Helen Staud | 17 | Wife | — | Illinois |
| 50 | Maureen Staud | 0 | Daughter | — | Illinois |
| 51 | Arthur Hickey | 47 | Lodger | Painter | Illinois |
| 52 | Martin Jr. Seymour | 56 | Head | Laborer | Illinois |
| 53 | Blanche Seymour | 50 | Wife | — | Illinois |
| 54 | Martin Jr. Seymour | 27 | Son | Laborer | Illinois |
| 55 | Catherine Seymour | 23 | Daughter | Stenographer | Illinois |
| 56 | James Seymour | 33 | Head | Iceman | Illinois |
| 57 | Ralph Seymour | 2 | Son | — | Illinois |
| 58 | James Jr. Seymour | 1 | Son | — | Illinois |
| 59 | Theresa Seymour | 28 | Wife | — | Illinois |
| 60 | Ralph Detwiler | 28 | Head | Laborer | Iowa |
| 61 | Mary Detwiler | 27 | Wife | — | Illinois |
| 62 | Donald Detwiler | 1 | Son | — | Illinois |
| 63 | Arthur Manual | 36 | Head | Timekeeper | Illinois |
| 64 | Min Manual | 70 | Mother | — | Illinois |
| 65 | Albert Clark | 61 | Head | Metal Worker | Illinois |
| 66 | Mary Clark THIS PERSON | 57 | Wife | — | Ireland |
| 67 | Irene Clark | 25 | Daughter | Nurse | Illinois |
| 68 | Rita Clark | 22 | Daughter | Nurse | Illinois |
| 69 | John Clark | 21 | Son | Clerk | Illinois |
| 70 | Ferdinand Renni | 35 | Head | Laborer | Pennsylvania |
| 71 | Agnes Renni | 31 | Wife | — | Illinois |
| 72 | Florence Renni | 10 | Daughter | — | Illinois |
| 73 | Ferdinand Jr. Renni | 6 | Son | — | Illinois |
| 74 | William Martin | 32 | Head | Laborer | Ireland |
| 75 | Agnes Martin | 31 | Wife | — | Illinois |
| 76 | William Jr. Martin | 9 | Son | — | Illinois |
| 77 | John Martin | 7 | Son | — | Illinois |
| 78 | Michael Collins | 71 | Boarder | Bartender | Illinois |
| 79 | Leo Brown | 25 | Head | Clerk | Illinois |
| 80 | Ann Brown | 21 | Wife | Telephone Operator | 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)