JK
John Kozlowski — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this John Kozlowski across the 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a head (b.~1887), then head of a 6-person household.
Age 53
b. ~1887
Male
Head
Born: Poland
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Kozlowski |
| Given Name | John |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 53 |
| Marital Status | Married |
| Birthplace | Poland |
| 1935 Residence (City) | Argo |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Additional Details | |
| Occupation | Foreman |
| Industry | Corn Refinery manufacturing |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 1560 |
| Highest Grade | No 8 |
| 1935 Residence | Same place |
| Birth Country | Poland |
| Birthplace (normalized) | poland |
| Occupation | Foreman |
| Township / Ward | Argo |
| Est. Birth Year | ~1887 |
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 |
|---|---|---|---|---|
| Joan Kozlowski | Daughter | — | 4 | ~1936 |
| Benny Kozlowski | Son | — | 18 | ~1922 |
| Joe Kozlowski | Son | — | 20 | ~1920 |
| John Kozlowski | Son | — | 7 | ~1933 |
| Alexandria Kozlowski | Spouse | — | 38 | ~1902 |
| John Kozlowski | Head | — | 53 | ~1887 |
Census Appearances
1930
Cook, Illinois
Head, age 44
Cook, Illinois · implied b. ~1886 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Kozlowski |
| Given Name | John |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 44 |
| Marital Status | Married |
| Birthplace | Poland |
| Naturalization Status | Naturalized |
| Year of Immigration | 1904 |
| Age at First Marriage | 22 |
| Father's Birthplace | Poland |
| Mother's Birthplace | Poland |
| Can Read/Write | Yes |
| Mother Tongue | Polish |
| Home Owned/Rented | R |
| Home Value / Rent | 17 |
| Birth Country | Poland |
| Birthplace (normalized) | poland |
1940
Cook-County, Illinois
Head, age 53
Cook-County, Illinois · implied b. ~1887 — 6 household members
| Surname | Kozlowski |
| Given Name | John |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 53 |
| Marital Status | Married |
| Birthplace | Poland |
| 1935 Residence (City) | Argo |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Occupation | Foreman |
| Industry | Corn Refinery manufacturing |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 1560 |
| Highest Grade | No 8 |
| 1935 Residence | Same place |
| Birth Country | Poland |
| Birthplace (normalized) | poland |
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 Kozlowski across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
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This person
Anchor record
John Kozlowski
Head · 1940 · age 53 · b. ~1887 · 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-t0627-00782-00462)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Oscar Lindquist | 50 | Head | Stone Mason | Sweden |
| 42 | Lillian Lindquist | 48 | Wife | — | Illinois |
| 43 | Steve Yerkovich | 48 | Head | Laborer | Austria |
| 44 | Francis Yerkovich | 46 | Wife | — | Austria |
| 45 | Michael Yerkovich | 27 | Son | Teller | West Virginia |
| 46 | Mary Yerkovich | 23 | Daughter | Laborer | West Virginia |
| 47 | Walter Yerkovich | 19 | Son | Laborer | Illinois |
| 48 | Joseph Yerkovich | 15 | Son | — | Illinois |
| 49 | John Polter | 47 | Head | Machinist | Illinois |
| 50 | Anna Polter | 34 | Wife | — | Germany |
| 51 | Richard Polter | 16 | Son | — | Illinois |
| 52 | Raymond Polter | 11 | Son | — | Illinois |
| 53 | George Lewis | 31 | Head | Laborer | Illinois |
| 54 | Margaret Lewis | 24 | Wife | — | Ohio |
| 55 | John Bernhart | 26 | Head | Laborer | Illinois |
| 56 | Vivian Bernhart | 22 | Wife | — | Illinois |
| 57 | Angelo Aldrighetti | 25 | Head | Assembler | Kansas |
| 58 | Louis Cinotto | 22 | Partner | Assembler | Kansas |
| 59 | Reno Aldrighetti | 21 | Partner | Assembler | Kansas |
| 60 | Leno Aldrighetti | 24 | Partner | Assembler | Kansas |
| 61 | Charles Bannon | 39 | Head | Proprietor | Illinois |
| 62 | Marie Bannon | 37 | Wife | Partner | Illinois |
| 63 | Jack Powers | 38 | Head | Machinist | Massachusetts |
| 64 | Lola Powers | 30 | Wife | Reborer | Michigan |
| 65 | William R. Mott | 54 | Head | Stationery Engineer | Illinois |
| 66 | Lena Mott | 57 | Wife | — | Indiana |
| 67 | Gene Mott | 24 | Son | Truck Driver | Illinois |
| 68 | Ruth Mott | 24 | Daughter-in-law | — | Illinois |
| 69 | Robert Mott | 2 | Grandson | — | Illinois |
| 70 | Betty Mott | 0 | Daughter-in-law | — | Illinois |
| 71 | Jack Haney | 29 | Head | Chemist | Illinois |
| 72 | Mary Haney | 30 | Wife | — | England |
| 73 | Kenneth Brown | 11 | Boarder | — | Massachusetts |
| 74 | Charles Kunik | 26 | Boarder | Chemist | Illinois |
| 75 | John Kozlowski THIS PERSON | 53 | Head | Foreman | Poland |
| 76 | Alexandria Kozlowski | 38 | Wife | — | Poland |
| 77 | Joe Kozlowski | 20 | Son | Bartender | Illinois |
| 78 | Benny Kozlowski | 18 | Son | — | Illinois |
| 79 | John Kozlowski | 7 | Son | — | Illinois |
| 80 | Joan Kozlowski | 4 | Daughter | — | 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)