MK
Mary Kozlowski — 1930 US Census Record
Linked across censuses1930 United States Federal Census · Cuyahoga, Ohio
Our Model Tree links this Mary Kozlowski across the 1930 and 1940 US Censuses in Cuyahoga, Ohio (XGBoost, ~Confirmed) — first a daughter (b.~1915), then head of a 7-person household.
Age 15
b. ~1915
Female
Daughter
Born: Ohio
Single
1930 Census Record Details
| Census Year | 1930 |
| Location | Cuyahoga, Ohio |
| Surname | Kozlowski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 15 |
| Marital Status | Single |
| Birthplace | Ohio |
| Father's Birthplace | Poland |
| Mother's Birthplace | New York |
| Additional Details | |
| Can Read/Write | Yes |
| Birth State | Ohio |
| Birth Country | United States |
| Birthplace (normalized) | ohio |
| Township / Ward | Cleveland |
| Est. Birth Year | ~1915 |
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 1930 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Mary Kozlowski | Daughter | — | 15 | ~1915 |
| Stella Kozlowski | Spouse | — | 41 | ~1889 |
| Frank Kozlowski | Son | — | 18 | ~1912 |
| Helen Kozlowski | Daughter | — | 10 | ~1920 |
| Joseph Kozlowski | Head | — | 50 | ~1880 |
| Joseph Kozlowski | Son | — | 22 | ~1908 |
| John Kozlowski | Son | — | 20 | ~1910 |
Census Appearances
1930
Cuyahoga, Ohio
Daughter, age 15
Cuyahoga, Ohio · implied b. ~1915 — 7 household members
| Surname | Kozlowski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 15 |
| Marital Status | Single |
| Birthplace | Ohio |
| Father's Birthplace | Poland |
| Mother's Birthplace | New York |
| Can Read/Write | Yes |
| Birth State | Ohio |
| Birth Country | United States |
| Birthplace (normalized) | ohio |
1940
Cuyahoga-County, Ohio
Other, age 25
Cuyahoga-County, Ohio · implied b. ~1915 — 40 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Kozlowske |
| Given Name | Mary |
| Sex | F |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | Ohio |
| 1935 Residence (City) | Cleveland |
| 1935 Residence (County) | Cuyahoga |
| Occupation | 03 |
| Industry | 03 |
| Hours Worked | 40 |
| Highest Grade | H-4 |
| 1935 Residence | Same place |
| Birth State | Ohio |
| Birth Country | United States |
| Birthplace (normalized) | ohio |
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 15 · b. ~1915 · Ohio
★ You are viewing this record
Sibling
John Kozlowski
Sibling · 1930 · age 20
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
Helen Kozlowski
Sibling · 1930 · age 10
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 — Cuyahoga, Ohio
Open full size
1930 US Federal Census — Cuyahoga, Ohio
Page Contents
50 people indexed on this census page (ia:1930:ohiocensus00reel1770:0835)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 51 | Frank Semplinski | 27 | Head | — | Poland |
| 52 | Alena Semplinski | 26 | Wife | — | Poland |
| 53 | Irene Semplinski | 5 | Daughter | — | Ohio |
| 54 | John Tuczynski | 53 | Head | — | Poland |
| 55 | Mary Tuczynski | 51 | Wife | — | Poland |
| 56 | Frank Mackiewicz | 35 | Head | Laborer | New Jersey |
| 57 | Stella Mackiewicz | 27 | Wife | — | Pennsylvania |
| 58 | Frank Mackiewicz | 8 | Son | — | Ohio |
| 59 | Sophie Mackiewicz | 6 | Daughter | — | Ohio |
| 60 | Edward Mackiewicz | 3 | Son | — | Ohio |
| 61 | Frank Kaminski | 40 | Lodger | Laborer | Poland |
| 62 | John Wojcik | 31 | Head | Laborer | Poland |
| 63 | Mary Wojcik | 26 | Wife | — | Ohio |
| 64 | John Wojcik | 9 | Son | — | Ohio |
| 65 | Edward Wojcik | 7 | Son | — | Ohio |
| 66 | Helen Wojcik | 5 | Daughter | — | Ohio |
| 67 | Stanley Wojcik | 1 | Son | — | Ohio |
| 68 | Frank Wojtkowski | 45 | Head | Laborer | Poland |
| 69 | Mary Wojtkowski | 38 | Wife | — | Poland |
| 70 | Helen Wojtkowski | 17 | Daughter | — | Ohio |
| 71 | Frank Wojtkowski | 16 | Son | — | Ohio |
| 72 | John Wojtkowski | 14 | Son | — | Ohio |
| 73 | Joseph Wojtkowski | 12 | Son | — | Ohio |
| 74 | Stella Wojtkowski | 10 | Daughter | — | Ohio |
| 75 | Josephine Wojtkowski | 8 | Daughter | — | Ohio |
| 76 | Sophie Wojtkowski | 6 | Daughter | — | Ohio |
| 77 | Edward Cieslak | 38 | Head | Laborer | Poland |
| 78 | Mary Cieslak | 35 | Wife | — | Poland |
| 79 | Joseph Kozlowski | 50 | Head | Laborer | Poland |
| 80 | Stella Kozlowski | 41 | Wife | — | New York |
| 81 | Joseph Kozlowski | 22 | Son | Laborer | Ohio |
| 82 | John Kozlowski | 20 | Son | Laborer | Ohio |
| 83 | Frank Kozlowski | 18 | Son | Laborer | Ohio |
| 84 | Mary Kozlowski THIS PERSON | 15 | Daughter | — | Ohio |
| 85 | Helen Kozlowski | 10 | Daughter | — | Ohio |
| 86 | Alex Siedlecki | 51 | Head | Laborer | Poland |
| 87 | Mary Siedlecki | 48 | Wife | — | Poland |
| 88 | Frank Siedlecki | 24 | Son | Laborer | Ohio |
| 89 | John Siedlecki | 22 | Son | Laborer | Ohio |
| 90 | Joe Siedlecki | 20 | Son | Laborer | Ohio |
| 91 | Paul Siedlecki | 18 | Son | Laborer | Ohio |
| 92 | Mary Siedlecki | 16 | Daughter | — | Ohio |
| 93 | Helen Siedlecki | 14 | Daughter | — | Ohio |
| 94 | Walter Siedlecki | 11 | Son | — | Ohio |
| 95 | Rose Siedlecki | 7 | Daughter | — | Ohio |
| 96 | Joe Kowalski | 65 | Head | Laborer | Poland |
| 97 | Mary Kowalski | 60 | Wife | — | Poland |
| 98 | Catherine Kowalski | 37 | Daughter | Operator | Ohio |
| 99 | John Kowalski | 32 | Son | — | Ohio |
| 100 | Sophie Kowalski | 28 | Daughter | — | Ohio |
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)