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Mary Kowalski — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Mary Kowalski across the 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a daughter (b.~1914), then head of a 7-person household.
Age 26
b. ~1914
Female
Daughter
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Kowalski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 26 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Summit Village |
| 1935 Residence (County) | Cook |
| Additional Details | |
| Occupation | Saleswoman |
| Industry | Retail Bakery |
| Class of Worker | PW |
| Hours Worked | 60 |
| Income (1939) | 520 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Occupation | Saleswoman |
| Township / Ward | Summit Village |
| Est. Birth Year | ~1914 |
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 |
|---|---|---|---|---|
| Anthony Kowalski | Head | — | 62 | ~1878 |
| Mary Kowalski | Daughter | — | 26 | ~1914 |
| Anthony Kowalski | Son | — | 28 | ~1912 |
| Mary Kowalski | Spouse | — | 60 | ~1880 |
| Florian Kowalski | Son | — | 13 | ~1927 |
| Casimir Kowalski | Son | — | 21 | ~1919 |
| Gertrude Kowalski | Daughter | — | 24 | ~1916 |
Census Appearances
1930
Cook, Illinois
Other, age 16
Cook, Illinois · implied b. ~1914 — 4 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Kowalski |
| Given Name | Mamie |
| Relationship to Head | Daughter-H |
| Sex | F |
| Color / Race | White |
| Age | 16 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Poland |
| Mother's Birthplace | Poland |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Cook-County, Illinois
Daughter, age 26
Cook-County, Illinois · implied b. ~1914 — 7 household members
| Surname | Kowalski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 26 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Summit Village |
| 1935 Residence (County) | Cook |
| Occupation | Saleswoman |
| Industry | Retail Bakery |
| Class of Worker | PW |
| Hours Worked | 60 |
| Income (1939) | 520 |
| Highest Grade | H 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 Kowalski across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Kowalski
Daughter · 1940 · age 26 · b. ~1914 · Illinois
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Sibling
Anthony Kowalski
Sibling · 1940 · age 28
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Florian Kowalski
Sibling · 1940 · age 13
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Casimir Kowalski
Sibling · 1940 · age 21
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Gertrude Kowalski
Sibling · 1940 · age 24
Source co-child of head (derived)
● Co-child · derived · ~0.88
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-t0627-00782-00443)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Francis Kislos | 28 | Head | Druggist | Illinois |
| 2 | Mildred Kislos | 26 | Wife | — | Illinois |
| 3 | Bernadette Kislos | 5 | Daughter | — | Illinois |
| 4 | Daniel Kislos | 5 | Son | — | Illinois |
| 5 | Emil Radtke | 66 | Head | — | Illinois |
| 6 | Leroy Radtke | 29 | Son | Truck Driver | Illinois |
| 7 | Dorothy Radtke | 28 | Daughter | Laborer | Illinois |
| 8 | Erwin Radtke | 19 | Son | Truck Driver | Illinois |
| 9 | Walter Radtke | 25 | Son | Truck Driver | Illinois |
| 10 | Wanda Radtke | 17 | Daughter | — | Illinois |
| 11 | Tajanis Mandlaki | 57 | Head | Laborer | Greece |
| 12 | Catherine Mandlaki | 48 | Wife | — | Greece |
| 13 | Anthony Kowalski | 62 | Head | Proprietor | Poland |
| 14 | Mary Kowalski | 60 | Wife | — | Poland |
| 15 | Anthony Jr. Kowalski | 28 | Son | Truck Driver | Illinois |
| 16 | Mary Kowalski THIS PERSON | 26 | Daughter | Saleswoman | Illinois |
| 17 | Gertrude Kowalski | 24 | Daughter | Cake Maker | Illinois |
| 18 | Casimir Kowalski | 21 | Son | Cake Maker | Illinois |
| 19 | Florian Kowalski | 13 | Son | — | Illinois |
| 20 | Victoria Melsnik | 66 | Head | — | Poland |
| 21 | Julius Melsnik | 36 | Son | Cashier | Poland |
| 22 | Sophia Melsnik | 30 | Daughter | Laborer | Poland |
| 23 | Jack Verkovich | 24 | Head | Truck Driver | West Virginia |
| 24 | Ignatia Verkovich | 20 | Wife | — | Illinois |
| 25 | Raymond Jones | 28 | Head | Laborer | Kentucky |
| 26 | Marie Jones | 28 | Wife | — | Illinois |
| 27 | Audrey Jones | 3 | Daughter | — | Illinois |
| 28 | John Kasak | 57 | Head | Laborer | Czecho-Slovakia |
| 29 | Anna Kasak | 54 | Wife | — | Slovakia |
| 30 | Joe Kasak | 32 | Son | Laborer | Illinois |
| 31 | Steve Kasak | 24 | Son | Laborer | Illinois |
| 32 | John Kasak | 15 | Son | — | Illinois |
| 33 | Everett Stater | 38 | Head | Painter | Indiana |
| 34 | Lillian Stater | 35 | Wife | — | Illinois |
| 35 | Martin Plakovic | 45 | Head | Laborer | Czecho-Slovakia |
| 36 | Marie Plakovic | 40 | Wife | — | Czecho-Slovakia |
| 37 | Emil James Plakovic | 20 | Son | Musician | Illinois |
| 38 | Elaine Plakovic | 16 | Daughter | — | Illinois |
| 39 | Wendel Jeno | 48 | Head | Laborer | Slovakia |
| 40 | Wendel Jeno | 24 | Son | Laborer | 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)