MO
Mary Olsen — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Mary Olsen across the 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a spouse (b.~1910), then head of a 7-person household.
Age 30
b. ~1910
Female
Spouse
Born: Illinois
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Olsen |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 30 |
| Marital Status | Married |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago City |
| 1935 Residence (County) | Cook |
| Additional Details | |
| Occupation | H.W. |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Occupation | H.W. |
| Township / Ward | Chicago City |
| Est. Birth Year | ~1910 |
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.
7 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Frank Olsen | Son | — | 20 | ~1920 |
| Louis Olsen | Son | — | 18 | ~1922 |
| Josephine Olsen | Daughter | — | 16 | ~1924 |
| Louis Olsen | Head | — | 37 | ~1903 |
| Mary Olsen | Daughter | — | 8 | ~1932 |
| Mary Olsen | Spouse | — | 30 | ~1910 |
| Dorothy Olsen | Daughter | — | 7 | ~1933 |
Census Appearances
1930
Cook, Illinois
Spouse, age 20
Cook, Illinois · implied b. ~1910 — 2 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Olson |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 20 |
| Marital Status | Married |
| Birthplace | Illinois |
| Age at First Marriage | 19 |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Minnesota |
| Occupation | none |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Cook-County, Illinois
Spouse, age 30
Cook-County, Illinois · implied b. ~1910 — 7 household members
| Surname | Olsen |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 30 |
| Marital Status | Married |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago City |
| 1935 Residence (County) | Cook |
| Occupation | H.W. |
| Highest Grade | Hs 4 |
| 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 Olsen across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
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This person
Anchor record
Mary Olsen
Spouse · 1940 · age 30 · b. ~1910 · 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-t0627-00987-00678)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Donald Berken | 7 | Son | — | Illinois |
| 42 | Theodore Berken | 5 | Son | — | Illinois |
| 43 | Raymond Berken | 3 | Son | — | Illinois |
| 44 | James Berken | 0 | Son | — | Illinois |
| 45 | Erich Blank | 38 | Head | Laborer | Germany |
| 46 | Frieda Blank | 32 | Wife | — | Germany |
| 47 | Howard Blank | 9 | Son | — | Illinois |
| 48 | James Blank | 7 | Son | — | Illinois |
| 49 | Harold Blank | 1 | Son | — | Illinois |
| 51 | Stephan Fabian | 54 | Head | Janitor | Austria |
| 52 | Mary Fabian | 46 | Wife | — | Austria |
| 53 | Joseph Fabian | 18 | Son | Carrier | New York |
| 54 | Stephan Fabian | 16 | Son | Carrier | Illinois |
| 55 | Louis Olsen | 37 | Head | Chauffeur | Illinois |
| 56 | Mary Olsen THIS PERSON | 30 | Wife | H.W. | Illinois |
| 57 | Frank Olsen | 20 | Son | Laborer | Illinois |
| 58 | Louis Olsen | 18 | Son | Mech Helper | Illinois |
| 59 | Josephine Olsen | 16 | Daughter | — | Illinois |
| 60 | Mary Lou Olsen | 8 | Daughter | — | Illinois |
| 61 | Dorothy Olsen | 7 | Daughter | — | Illinois |
| 62 | Helen Romanowski | 55 | Head | Cook | Russia |
| 63 | Hardy Romanowski | 22 | Daughter | Stenographer | Illinois |
| 64 | Helen Romanowski | 21 | Daughter | Biller | Illinois |
| 65 | John Rusen | 28 | Head | Traffic Eng. | Illinois |
| 66 | Henrietta Rusen | 27 | Wife | — | Illinois |
| 67 | John Rusen | 1 | Son | — | Illinois |
| 68 | Michael Rusen | 0 | Infant | — | Illinois |
| 69 | Betty Argalas | 20 | Maid | Housemaid | Wisconsin |
| 70 | Mary Holland | 58 | Head | — | Indiana |
| 71 | Caroline Holland | 30 | Daughter | Stenographer | Illinois |
| 72 | Walter Mullen | 39 | Head | Dentist | Mississippi |
| 73 | Maurine Mullen | 32 | Wife | — | Mississippi |
| 74 | Walter Jr Mullen | 5 | Son | — | Illinois |
| 75 | Franklin Mullen | 3 | Son | — | Illinois |
| 76 | Eugene Reiner | 36 | Head | Architect | Minnesota |
| 77 | Kathryn Reiner | 36 | Wife | Clerk | Illinois |
| 78 | Eugene Reiner | 7 | Son | — | Illinois |
| 79 | Mary Reiner | 5 | Daughter | — | Illinois |
| 80 | Richard Reiner | 4 | Son | — | 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)