MK
Mary Kozlowski — 1930 US Census Record
Linked across censuses1930 United States Federal Census · Cook, Illinois
Our Model Tree links this Mary Kozlowski across the 1930 and 1940 US Censuses in Cook, Illinois (XGBoost, ~Confirmed) — first a daughter (b.~1920), then head of a 9-person household.
Age 10
b. ~1920
Female
Daughter
Born: Illinois
Single
1930 Census Record Details
| Census Year | 1930 |
| Location | Cook, Illinois |
| Surname | Kozlowski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 10 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Poland |
| Mother's Birthplace | Poland |
| Additional Details | |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Township / Ward | Chicago |
| Est. Birth Year | ~1920 |
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.
9 people recorded at the same address in the 1930 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Stanley Kozlowski | Head | — | 49 | ~1881 |
| Edward Kozlowski | Son | — | 20 | ~1910 |
| Mary Kozlowski | Daughter | — | 10 | ~1920 |
| Joseph Kozlowski | Son | — | 22 | ~1908 |
| Frank Kozlowski | Son | — | 18 | ~1912 |
| Stanley Kozlowski | Son | — | 14 | ~1916 |
| Raymond Kozlowski | Son | — | 12 | ~1918 |
| Leo Kozlowski | Son | — | 16 | ~1914 |
| Bernice Kozlowski | Spouse | — | 43 | ~1887 |
Census Appearances
1930
Cook, Illinois
Daughter, age 10
Cook, Illinois · implied b. ~1920 — 9 household members
| Surname | Kozlowski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 10 |
| 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 21
Cook-County, Illinois · implied b. ~1919 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Koslowski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 21 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Occupation | Sales Clerk |
| Industry | Retail Grocery Store |
| Class of Worker | PW |
| Hours Worked | 50 |
| Income (1939) | 614 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same House |
| 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 Kozlowski across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Kozlowski
Daughter · 1930 · age 10 · b. ~1920 · Illinois
★ You are viewing this record
Sibling
Edward Kozlowski
Sibling · 1930 · age 20
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Raymond Kozlowski
Sibling · 1930 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Stanley Kozlowski
Sibling · 1930 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Frank Kozlowski
Sibling · 1930 · age 18
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Leo Kozlowski
Sibling · 1930 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Joseph Kozlowski
Sibling · 1930 · age 22
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
1930 US Federal Census — Cook, Illinois
Open full size
1930 US Federal Census — Cook, Illinois
Page Contents
50 people indexed on this census page (ia:1930:illinoiscensus00reel463:0910)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 51 | Felix Gorski | 47 | Head | Laborer | Poland |
| 52 | Mary Gorski | 40 | Wife | — | Poland |
| 53 | Florence Gorski | 16 | Daughter | — | Illinois |
| 54 | Lorraine Gorski | 12 | Daughter | — | Illinois |
| 55 | Teddy Gorski | 10 | Son | — | Illinois |
| 56 | Edward Gorski | 8 | Son | — | Illinois |
| 57 | Chester Gorski | 6 | Son | — | Illinois |
| 58 | Raymond Gorski | 4 | Son | — | Illinois |
| 59 | Sylvester Gorski | 2 | Son | — | Illinois |
| 60 | Leo Gorski | 1 | Son | — | Illinois |
| 61 | Joseph Gorski | 14 | Son | — | Illinois |
| 62 | Stanley Gorski | 12 | Son | — | Illinois |
| 63 | Helen Gorski | 10 | Daughter | — | Illinois |
| 64 | Frank Gorski | 8 | Son | — | Illinois |
| 65 | Edward Gorski | 6 | Son | — | Illinois |
| 66 | Ray Gorski | 4 | Son | — | Illinois |
| 67 | Leo Gorski | 1 | Son | — | Illinois |
| 68 | Martha Hutchinson | 46 | Head | — | Illinois |
| 69 | Earl Hutchinson | 26 | Son | Laborer | Illinois |
| 70 | Lester Hutchinson | 24 | Son | — | Illinois |
| 71 | Arthur Hutchinson | 20 | Son | — | Illinois |
| 72 | William Hutchinson | 18 | Son | Laborer | Ohio |
| 73 | Myerson Hutchinson | 13 | Son | — | Illinois |
| 74 | Stanley Kozlowski | 49 | Head | Laborer | Poland |
| 75 | Bernice Kozlowski | 43 | Wife | — | Poland |
| 76 | Joseph Kozlowski | 22 | Son | — | Illinois |
| 77 | Edward Kozlowski | 20 | Son | — | Illinois |
| 78 | Frank Kozlowski | 18 | Son | Helper | Illinois |
| 79 | Leo Kozlowski | 16 | Son | — | Illinois |
| 80 | Stanley Kozlowski | 14 | Son | Helper | Illinois |
| 81 | Raymond Kozlowski | 12 | Son | — | Illinois |
| 82 | Mary Kozlowski THIS PERSON | 10 | Daughter | — | Illinois |
| 83 | Joseph Petrucci | 54 | Head | Laborer | Italy |
| 84 | Lucy Petrucci | 47 | Wife | — | Italy |
| 85 | Mary Petrucci | 21 | Daughter | — | Italy |
| 86 | Carmella Petrucci | 18 | Daughter | — | Illinois |
| 87 | Anne Petrucci | 15 | Daughter | — | Illinois |
| 88 | Rose Petrucci | 12 | Daughter | — | Illinois |
| 89 | Theresa Petrucci | 11 | Daughter | — | Illinois |
| 90 | Frank Cervello | 45 | Head | — | Italy |
| 91 | Mary Cervello | 43 | Wife | — | Italy |
| 92 | Joseph Cervello | 21 | Son | — | Illinois |
| 93 | Clara Cervello | 17 | Daughter | — | Illinois |
| 94 | Dominick Cervello | 13 | Son | — | Illinois |
| 95 | Charles Peppe | 41 | Head | Laborer | Italy |
| 96 | Grace Peppe | 35 | Wife | — | Illinois |
| 97 | Charles Jr. Peppe | 6 | Son | — | Illinois |
| 98 | Theresa Peppe | 2 | Daughter | — | Illinois |
| 99 | Salvatore Leone | 43 | Head | Operator | Italy |
| 100 | Mildred Leone | 36 | Wife | — | Italy |
About This Record & Model Tree
This record was independently indexed by YourRoots from the 1930 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)