MK
Mary Kozlowski — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Baltimore-City-County, Maryland
Our Model Tree links this Mary Kozlowski across the 1930 and 1940 US Censuses in Baltimore-City-County, Maryland (XGBoost, ~Confirmed) — first a daughter (b.~1923), then head of a 7-person household.
Age 17
b. ~1923
Female
Daughter
Born: Maryland
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Baltimore-City-County, Maryland |
| Surname | Kozlowski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 17 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Baltimore City |
| 1935 Residence (County) | Baltimore City |
| Additional Details | |
| Occupation | Packer |
| Industry | Packing House |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 312 |
| Highest Grade | 7 |
| 1935 Residence | Same Place |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
| Occupation | Packer |
| Township / Ward | Baltimore City |
| Est. Birth Year | ~1923 |
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 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Joseph Kozlowski | Head | — | 52 | ~1888 |
| Frank Kozlowski | Son | — | 29 | ~1911 |
| Stephen Kozlowski | Son | — | 23 | ~1917 |
| Alexander Kozlowski | Son | — | 9 | ~1931 |
| Alexandria Kozlowski | Spouse | — | 51 | ~1889 |
| Mary Kozlowski | Daughter | — | 17 | ~1923 |
| Sophie Kozlowski | Daughter | — | 13 | ~1927 |
Census Appearances
1930
Baltimore, Maryland
Daughter, age 6
Baltimore, Maryland · implied b. ~1924 — 8 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Kozlowski |
| Given Name | Mildred |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 6 |
| Marital Status | Single |
| Birthplace | Maryland |
| Father's Birthplace | Poland |
| Mother's Birthplace | Poland |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
1940
Baltimore-City-County, Maryland
Daughter, age 17
Baltimore-City-County, Maryland · implied b. ~1923 — 7 household members
| Surname | Kozlowski |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 17 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Baltimore City |
| 1935 Residence (County) | Baltimore City |
| Occupation | Packer |
| Industry | Packing House |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 312 |
| Highest Grade | 7 |
| 1935 Residence | Same Place |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
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 · 1940 · age 17 · b. ~1923 · Maryland
★ You are viewing this record
Sibling
Alexander Kozlowski
Sibling · 1940 · age 9
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Stephen Kozlowski
Sibling · 1940 · age 23
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Sophie Kozlowski
Sibling · 1940 · age 13
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Frank Kozlowski
Sibling · 1940 · age 29
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 — Baltimore-City-County, Maryland
Open full size
1940 US Federal Census — Baltimore-City-County, Maryland
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01508-00576)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Edward Plewicki | 35 | Head | Labourer | Maryland |
| 42 | Anna Plewicki | 26 | Wife | — | Maryland |
| 43 | Frank R. Muzewski | 53 | Head | Labourer | Maryland |
| 44 | Marion Mithom | 56 | Head | Capt Of Barge | Maryland |
| 45 | Marie Mithom | 48 | Wife | — | Maryland |
| 46 | Fred Engler | 55 | Head | Huckster | Maryland |
| 47 | John Lynch | 52 | Head | Laborer | Ireland |
| 48 | Mary D. Lynch | 52 | Wife | — | Ireland |
| 49 | Maryann Boyer | 61 | Head | — | Maryland |
| 50 | Joseph Kozlowski | 52 | Head | Stevadore | Poland |
| 51 | Alexandria Kozlowski | 51 | Wife | — | Poland |
| 52 | Frank Kozlowski | 29 | Son | Trucker | Maryland |
| 53 | Stephen Kozlowski | 23 | Son | — | Maryland |
| 54 | Mary Kozlowski THIS PERSON | 17 | Daughter | Packer | Maryland |
| 55 | Sophie Kozlowski | 13 | Daughter | — | Maryland |
| 56 | Alexander Kozlowski | 9 | Son | — | Maryland |
| 57 | William Stasiak | 70 | Head | — | Poland |
| 58 | Stella Stasiak | 75 | Wife | — | Poland |
| 59 | Marion Stasiak | 35 | Son | Caretaker | Maryland |
| 60 | Joseph Michnowicz | 35 | Head | Laborer | Wilmington, Del. |
| 61 | Sophie Michnowicz | 37 | Wife | Finilady | Maryland |
| 62 | Sylvia Michnowicz | 13 | Daughter | — | Maryland |
| 63 | Geraldine Michnowicz | 9 | Daughter | — | Maryland |
| 64 | Wladyslaw Ropczynski | 46 | Head | Stevadore | Poland |
| 65 | Stanislawa Ropczynski | 45 | Wife | — | Maryland |
| 66 | Edward Ropczynski | 19 | Son | Furnisher | Maryland |
| 67 | John Ropczynski | 18 | Son | Labourer | Maryland |
| 68 | Alice Ropczynski | 17 | Daughter | Operator | Maryland |
| 69 | Eleanora Ropczynski | 15 | Daughter | — | Maryland |
| 70 | Daniel Ropczynski | 13 | Son | — | Maryland |
| 71 | Alfreda Ropczynski | 12 | Daughter | — | Maryland |
| 72 | Walter Ropczynski | 10 | Son | — | Maryland |
| 73 | Marcella Ropczynski | 8 | Daughter | — | Maryland |
| 74 | Dorothy Ropczynski | 5 | Daughter | — | Maryland |
| 75 | Frank Ropczynski | 1 | Son | — | Maryland |
| 76 | Michael Struzykowski | 37 | Brother in Law | Stevadore | Maryland |
| 77 | Frances Woznowska | 32 | Head | Operator | Maryland |
| 78 | Frances Woznowska | 14 | Daughter | — | Maryland |
| 79 | Bernard Woznowska | 3 | Son | — | Maryland |
| 80 | Ida Mcleod | 76 | Head | — | Maryland |
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)