JK
John Kowalski — 1940 US Census Record
Model Tree available1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this John Kowalski across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed), with identified parents George & Walter — first a son (b.~1916), then head of a 6-person household.
Age 24
b. ~1916
Male
Son
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Kowalski |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 24 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Additional Details | |
| Occupation | Labour |
| Industry | Lumber Co |
| Class of Worker | PW |
| Hours Worked | 3 |
| Income (1939) | 988 |
| Highest Grade | No 7 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Occupation | Labour |
| Township / Ward | Chicago |
| Est. Birth Year | ~1916 |
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.
6 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Fillena Kowalski | Head | — | 44 | ~1896 |
| Frank Kowalski | Son | — | 23 | ~1917 |
| Richard Kowalski | Son | — | 8 | ~1932 |
| John Kowalski | Son | — | 24 | ~1916 |
| Joseph Kowalski | Son | — | 21 | ~1919 |
| George Kowalski | Son | — | 11 | ~1929 |
Census Appearances
1920
Cook, Illinois
Son, age 3
Cook, Illinois · implied b. ~1917 — 4 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Kowalski |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 3 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Poland |
| Mother's Birthplace | Poland |
| Mother Tongue | Polish |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1930
Cook, Illinois
Son, age 13
Cook, Illinois · implied b. ~1917 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Kowalski |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 13 |
| 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
Son, age 24
Cook-County, Illinois · implied b. ~1916 — 6 household members
| Surname | Kowalski |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 24 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Occupation | Labour |
| Industry | Lumber Co |
| Class of Worker | PW |
| Hours Worked | 3 |
| Income (1939) | 988 |
| Highest Grade | No 7 |
| 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 John Kowalski across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father George Kowalski (~0.92 confidence) and father Walter Kowalski (~0.92 confidence) and mother Mary Kowalski (~0.92 confidence) and mother Fillena Kowalski (~0.92 confidence). The pedigree spans 1 generation with 4 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
George Kowalski
b. ~1885
Source father
● Household
· direct · ~0.92
Father
Walter Kowalski
b. ~1893
Source father
● Household
· direct · ~0.92
Mother
Mary Kowalski
b. ~1895
Source mother
● Household
· direct · ~0.92
Mother
Fillena Kowalski
b. ~1896
Source mother
● Household
· direct · ~0.92
This person
Anchor record
John Kowalski
Son · 1940 · age 24 · b. ~1916 · Illinois
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Sibling
Frank Kowalski
Sibling · 1940 · age 23
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
George Kowalski
Sibling · 1940 · age 11
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Richard Kowalski
Sibling · 1940 · age 8
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Joseph Kowalski
Sibling · 1940 · age 21
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
39 people indexed on this census page (nara:1940:m-t0627-00985-00161)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Henry Sobczynski | 18 | Son | — | Illinois |
| 2 | Mary Sobczynski | 15 | Daughter | — | Illinois |
| 3 | Bruno Kuzmicki | 48 | Head | Clerk | Latvia |
| 4 | Helen Kuzmicki | 46 | Wife | — | Latvia |
| 5 | Violet Kuzmicki | 18 | Daughter | — | Latvia |
| 6 | Walter Kuzmicki | 15 | Son | — | Illinois |
| 7 | Anton Chruscinski | 68 | Head | — | Poland |
| 8 | William Christian | 44 | Head | Labour | Missouri |
| 9 | Ethel Christian | 35 | Wife | — | Missouri |
| 10 | Homer Ross | 12 | Stepchild | — | Illinois |
| 11 | Helen Ross | 15 | Stepchild | Night Guard | Missouri |
| 12 | Walter Czajkowski | 66 | Head | — | Poland |
| 13 | Stella Czajkowski | 47 | Wife | — | Poland |
| 14 | Eleonore Czajkowski | 22 | Daughter | — | Illinois |
| 15 | Richard Czajkowski | 19 | Son | New Worker | Illinois |
| 16 | Robert Czajkowski | 6 | Son | — | Illinois |
| 17 | Fillena Kowalski | 44 | Head | — | Illinois |
| 18 | John Kowalski THIS PERSON | 24 | Son | Labour | Illinois |
| 19 | Frank Kowalski | 23 | Son | Wash Clothes | Illinois |
| 20 | Joseph Kowalski | 21 | Son | — | Illinois |
| 21 | George Kowalski | 11 | Son | — | Illinois |
| 22 | Richard Kowalski | 8 | Son | — | Illinois |
| 23 | August Baungard | 58 | Head | Labour | Poland |
| 24 | Frances Baungard | 58 | Wife | — | Poland |
| 25 | Lydia Baungard | 17 | Daughter | — | Illinois |
| 26 | Stanley Perr | 44 | Head | Painter | Poland |
| 27 | Elizabeth Perr | 45 | Wife | — | Wisconsin |
| 28 | Frank Perr | 19 | Son | Helper | Illinois |
| 29 | Raymond Perr | 17 | Son | — | Illinois |
| 30 | Charlie Gallas | 52 | Head | Labour | Illinois |
| 31 | Anna Gallas | 50 | Wife | — | Illinois |
| 32 | Gladys Gallas | 26 | Daughter | Seamstress | Illinois |
| 33 | Adam Lessner | 48 | Lodger | Labour | Illinois |
| 34 | Mitchell Pogorzelski | 44 | Head | Stock Clerk | Poland |
| 35 | Martha Pogorzelski | 45 | Wife | — | Poland |
| 36 | Anna Jakack | 22 | Daughter | Seamstress | Illinois |
| 37 | Stanley Jakack | 18 | Son | New Worker | Illinois |
| 38 | John Great | 47 | Head | Clerk | Poland |
| 39 | Mary Great | 44 | Wife | — | Pennsylvania |
Pedigree Summary
John + 4 siblings
Gen 1 · 4 parents
~0.92
Max depth 4 (1900–1950 window)
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)