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Mary Brennan — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Mary Brennan across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a spouse (b.~1888), then head of a 4-person household.
Age 52
b. ~1888
Female
Spouse
Born: Ireland
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Brennan |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 52 |
| Marital Status | Married |
| Birthplace | Ireland |
| 1935 Residence (City) | Chicago City |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Additional Details | |
| Highest Grade | No 6 |
| 1935 Residence | Same House |
| Birth Country | Ireland |
| Birthplace (normalized) | ireland |
| Township / Ward | Chicago City |
| Est. Birth Year | ~1888 |
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.
4 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Mary Brennan | Daughter | — | 22 | ~1918 |
| Thomas Brennan | Head | — | 53 | ~1887 |
| Henry Brennan | Son | — | 20 | ~1920 |
| Mary Brennan | Spouse | — | 52 | ~1888 |
Census Appearances
1920
Cook, Illinois
Spouse, age 38
Cook, Illinois · implied b. ~1882 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Brennan |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 38 |
| Marital Status | Married |
| Birthplace | Ireland |
| Year of Immigration | 1911 |
| Naturalization Status | Alien |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Mother Tongue | English |
| Birth Country | Ireland |
| Birthplace (normalized) | ireland |
1930
Cook, Illinois
Spouse, age 45
Cook, Illinois · implied b. ~1885 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Brennan |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 45 |
| Marital Status | Married |
| Birthplace | Ireland |
| Naturalization Status | Naturalized |
| Year of Immigration | 1915 |
| Age at First Marriage | 20 |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Can Read/Write | Yes |
| Mother Tongue | English |
| Birth Country | Ireland |
| Birthplace (normalized) | ireland |
1940
Cook-County, Illinois
Spouse, age 52
Cook-County, Illinois · implied b. ~1888 — 4 household members
| Surname | Brennan |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 52 |
| Marital Status | Married |
| Birthplace | Ireland |
| 1935 Residence (City) | Chicago City |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Highest Grade | No 6 |
| 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 Brennan 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 Brennan
Spouse · 1940 · age 52 · b. ~1888 · 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
39 people indexed on this census page (nara:1940:m-t0627-00959-00032)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Irma M. Mckay | 37 | Wife | — | Illinois |
| 42 | Shirley J. Mckay | 16 | Daughter | — | Illinois |
| 43 | Roberta E. Mckay | 2 | Daughter | — | Illinois |
| 44 | Margaret M. Walsh | 65 | Head | — | Illinois |
| 46 | William A. Ford | 46 | Head | Roll Hand | New York |
| 47 | Charlotte B. Ford | 46 | Wife | — | Missouri |
| 48 | Milburn A. Ford | 20 | Son | New Worker | Missouri |
| 49 | Raymond W. Ford | 17 | Son | — | Missouri |
| 50 | Lloyd M. Pelham | 29 | Nephew | Roll Turner | Missouri |
| 51 | Thomas Brennan | 53 | Head | Motorman | England |
| 52 | Mary Brennan THIS PERSON | 52 | Wife | — | Ireland |
| 53 | Mary Brennan | 22 | Daughter | — | Illinois |
| 54 | Henry P. Brennan | 20 | Son | Shipping Clerk | Illinois |
| 55 | Horace M. Peach | 51 | Head | Secretary | Illinois |
| 56 | Olinda A. Peach | 45 | Wife | — | Illinois |
| 57 | Martha E. Peach | 18 | Daughter | — | Illinois |
| 58 | Robert W. Peach | 15 | Son | — | Illinois |
| 59 | William H. Mckay | 65 | Head | Officer | Illinois |
| 60 | Hattie B. Mckay | 60 | Wife | — | Illinois |
| 61 | Lorraine H. Mckay | 20 | Daughter | Junior Librarian | Illinois |
| 62 | Mary Ruger | 61 | Head | — | England |
| 63 | Harmon B. Ruger | 37 | Son | Freight Clerk | Illinois |
| 64 | John C. Ruger | 24 | Son | Laborer | Illinois |
| 65 | Virgil B. Cox | 29 | Head | Fireman | Indiana |
| 66 | Dorothy L. Cox | 26 | Wife | — | Indiana |
| 67 | Barbara J. Cox | 5 | Daughter | — | Indiana |
| 68 | Aaron O. Cox | 85 | Father | — | Indiana |
| 69 | John E. Stalybe | 43 | Head | Motorman | Illinois |
| 70 | Ellen L. Stalybe | 42 | Wife | — | Illinois |
| 71 | John E. Stalybe | 19 | Son | Shipping Clerk | Illinois |
| 72 | Dona J. Stalybe | 13 | Daughter | — | Illinois |
| 73 | William R. Stalybe | 7 | Son | — | Illinois |
| 74 | Weymouth E. Stark | 47 | Head | Water Tender | Illinois |
| 75 | Anna M. Stark | 40 | Wife | — | Illinois |
| 76 | Grace K. Stark | 19 | Daughter | Clerical | Illinois |
| 77 | Doris J. Stark | 13 | Daughter | — | Illinois |
| 78 | Catherine A. Thomas | 68 | Mother-in-law | — | Maine |
| 79 | Carl D. Giesen | 41 | Head | Accountant | Illinois |
| 80 | Ruth M. Giesen | 37 | Wife | — | 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)