MK
Mary Kozlowski — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Mercer-County, New Jersey
Our Model Tree links this Mary Kozlowski across the 1930 and 1940 US Censuses in Mercer-County, New Jersey (XGBoost, ~Confirmed) — first a spouse (b.~1903), then head of a 6-person household.
Age 37
b. ~1903
Female
Spouse
Born: Poland
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Mercer-County, New Jersey |
| Surname | Kozlowski |
| Given Name | Mary H. |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 37 |
| Marital Status | Married |
| Birthplace | Poland |
| 1935 Residence (City) | Hamilton Township |
| 1935 Residence (County) | Mercer |
| Naturalization Status | Naturalized |
| Additional Details | |
| Class of Worker | 0 |
| Highest Grade | No 3 |
| 1935 Residence | Same Place |
| Birth Country | Poland |
| Birthplace (normalized) | poland |
| Township / Ward | Hamilton Township |
| Est. Birth Year | ~1903 |
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 Mary | Age | Birth yr |
|---|---|---|---|---|
| Lillian Kozlowski | Daughter | — | 7 | ~1933 |
| Joseph Kozlowski | Head | — | 50 | ~1890 |
| Helen Kozlowski | Daughter | — | 12 | ~1928 |
| George Kozlowski | Son | — | 14 | ~1926 |
| Joseph Kozlowski | Son | — | 9 | ~1931 |
| Mary Kozlowski | Spouse | — | 37 | ~1903 |
Census Appearances
1930
Union, New …
Spouse, age 27
Union, New Jersey · implied b. ~1903 — 4 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Koslowski |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 27 |
| Marital Status | Married |
| Birthplace | Poland |
| Naturalization Status | Naturalized |
| Year of Immigration | 1914 |
| Age at First Marriage | 18 |
| Father's Birthplace | Poland |
| Mother's Birthplace | Poland |
| Can Read/Write | Yes |
| Mother Tongue | Polish |
| Birth Country | Poland |
| Birthplace (normalized) | poland |
1940
Mercer-County, New …
Spouse, age 37
Mercer-County, New Jersey · implied b. ~1903 — 6 household members
| Surname | Kozlowski |
| Given Name | Mary H. |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 37 |
| Marital Status | Married |
| Birthplace | Poland |
| 1935 Residence (City) | Hamilton Township |
| 1935 Residence (County) | Mercer |
| Naturalization Status | Naturalized |
| Class of Worker | 0 |
| Highest Grade | No 3 |
| 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 Mary Kozlowski across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
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This person
Anchor record
Mary Kozlowski
Spouse · 1940 · age 37 · b. ~1903 · New Jersey
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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 — Mercer-County, New Jersey
Open full size
1940 US Federal Census — Mercer-County, New Jersey
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-02356-00553)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Ruth Robbins | 19 | Daughter | Candy Packer | New Jersey |
| 2 | Lillian Robbins | 16 | Daughter | — | New Jersey |
| 3 | William B Robbins | 87 | Father | — | New Jersey |
| 4 | Jacob Blackwell | 60 | Head | Farmer | New Jersey |
| 5 | Rose Blackwell | 57 | Wife | — | Virginia |
| 6 | Anna Blackwell | 17 | Daughter | — | New Jersey |
| 7 | John Johnson | 34 | Head | — | Georgia |
| 8 | Elizabeth Johnson | 23 | Wife | Laborer - Digging | Virginia |
| 9 | Leroy Johnson | 3 | Son | 0 | New Jersey |
| 10 | Frank Robbins | 66 | Head | Carpenter | New Jersey |
| 11 | Addie Robbins | 63 | Wife | — | New Jersey |
| 12 | Leon Robbins | 43 | Son | Farm Laborer | New Jersey |
| 13 | Wesley J. Bendey | 48 | Head | Mixer | New Jersey |
| 14 | George W. Bendey | 80 | Father | — | New Jersey |
| 15 | Clarabella Bendey | 70 | Mother | — | New Jersey |
| 16 | William Bendey | 34 | Brother | Farm Laborer | New Jersey |
| 17 | Frank Bendey | 32 | Brother | Laborer | New Jersey |
| 18 | Joseph Sr. Kardos | 54 | Head | Belt Maker | Hungary |
| 19 | Helen Kardos | 53 | Wife | — | Hungary |
| 20 | Joseph Jr. Kardos | 31 | Son | — | New Jersey |
| 21 | William Kardos | 23 | Son | Hosemaker | New Jersey |
| 22 | Julius Kardos | 20 | Son | Apprentice Painter | New Jersey |
| 23 | Frank Kardos | 16 | Son | — | New Jersey |
| 24 | Elmer Kardos | 13 | Son | — | New Jersey |
| 25 | Louis Kardos | 11 | Son | — | New Jersey |
| 26 | Thomas Siorek | 70 | Head | — | Poland |
| 27 | Antoinette Siorek | 68 | Wife | — | Poland |
| 28 | Valentine Siorek | 25 | Son | Tile Setter | New Jersey |
| 29 | Stanley Siorek | 23 | Son | Farmer | New Jersey |
| 30 | Joseph Kozlowski | 50 | Head | Farmer | Poland |
| 31 | Mary H. Kozlowski THIS PERSON | 37 | Wife | — | Poland |
| 32 | George Kozlowski | 14 | Son | — | New Jersey |
| 33 | Helen Kozlowski | 12 | Daughter | — | New Jersey |
| 34 | Joseph Kozlowski | 9 | Son | — | New Jersey |
| 35 | Lillian Kozlowski | 7 | Daughter | — | New Jersey |
| 36 | Frank Sr. Munger | 42 | Head | Mixer | New York |
| 37 | Katherine M. Munger | 27 | Wife | — | New Jersey |
| 38 | Katherine M. Munger | 7 | Daughter | — | New Jersey |
| 39 | Frank Jr. Munger | 4 | Son | 0 | New Jersey |
| 40 | Richard Munger | 0 | Son | 0 | New Jersey |
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)