JL
John Leahy — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Worcester-County, Massachusetts
Our Model Tree links this John Leahy across the 1930 and 1940 US Censuses in Worcester-County, Massachusetts (XGBoost, ~Confirmed) — first a son (b.~1924), then head of a 9-person household.
Age 16
b. ~1924
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Worcester-County, Massachusetts |
| Surname | Leahy |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 16 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Worcester |
| 1935 Residence (County) | Worcester |
| Additional Details | |
| Highest Grade | Hs 1 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Est. Birth Year | ~1924 |
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 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Patrick Leahy | Head | — | 53 | ~1887 |
| Rita Leahy | Daughter | — | 18 | ~1922 |
| Mary Leahy | Daughter | — | 20 | ~1920 |
| Joseph Leahy | Son | — | 24 | ~1916 |
| Vincent Leahy | Son | — | 13 | ~1927 |
| Dorothy Leahy | Daughter | — | 10 | ~1930 |
| John Leahy | Son | — | 16 | ~1924 |
| Elizabeth Leahy | Daughter | — | 22 | ~1918 |
| Nora Leahy | Spouse | — | 48 | ~1892 |
Census Appearances
1930
Worcester, Massachusetts
Son, age 6
Worcester, Massachusetts · implied b. ~1924 — 9 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leahy |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 6 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Ireland Free S |
| Mother's Birthplace | Ireland Free S |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Worcester-County, Massachusetts
Son, age 16
Worcester-County, Massachusetts · implied b. ~1924 — 9 household members
| Surname | Leahy |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 16 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Worcester |
| 1935 Residence (County) | Worcester |
| Highest Grade | Hs 1 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
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 Leahy across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
John Leahy
Son · 1940 · age 16 · b. ~1924 · Massachusetts
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Sibling
Joseph Leahy
Sibling · 1940 · age 24
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Vincent Leahy
Sibling · 1940 · age 13
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Rita Leahy
Sibling · 1940 · age 18
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Dorothy Leahy
Sibling · 1940 · age 10
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Mary Leahy
Sibling · 1940 · age 20
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Elizabeth Leahy
Sibling · 1940 · 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
1940 US Federal Census — Worcester-County, Massachusetts
Open full size
1940 US Federal Census — Worcester-County, Massachusetts
Page Contents
39 people indexed on this census page (nara:1940:m-t0627-01716-00547)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Mary Wojnarowicz | 25 | Daughter | Stitcher | Rhode Island |
| 42 | Stanley Wojnarowicz | 26 | Son | Watchman | Massachusetts |
| 43 | Frances Wojnarowicz | 19 | Daughter | Heel-Coverer | Massachusetts |
| 44 | Joseph Wojnarowicz | 16 | Son | — | Massachusetts |
| 45 | Helen Wojnarowicz | 13 | Daughter | — | Massachusetts |
| 46 | Thaddeus Wojnarowicz | 12 | Son | — | Massachusetts |
| 47 | Dennis Marmat | 45 | Head | Laborer | Albania |
| 48 | James Marmat | 19 | Son | New Worker | Massachusetts |
| 49 | Edward (Ab) Marmat | 18 | Son | New Worker | Massachusetts |
| 50 | Gerald Marmat | 14 | Son | — | Massachusetts |
| 51 | George Marmat | 12 | Son | — | Massachusetts |
| 52 | Patrick J. Leahy | 53 | Head | Janitor | Ireland Free State |
| 53 | Nora Leahy | 48 | Wife | — | Ireland Free State |
| 54 | Joseph A. Leahy | 24 | Son | Substitute | Massachusetts |
| 55 | Elizabeth Leahy | 22 | Daughter | Finisher | Massachusetts |
| 56 | Mary Leahy | 20 | Daughter | Elevator Operator | Massachusetts |
| 57 | Rita Leahy | 18 | Daughter | — | Massachusetts |
| 58 | John Leahy THIS PERSON | 16 | Son | — | Massachusetts |
| 59 | Vincent Leahy | 13 | Son | — | Massachusetts |
| 60 | Dorothy Leahy | 10 | Daughter | — | Massachusetts |
| 62 | August Dziadul | 44 | Head | Baker | Poland |
| 63 | Alice Dziadul | 33 | Wife | — | Poland |
| 64 | Joseph Dziadul | 15 | Son | — | Massachusetts |
| 65 | Frank Dziadul | 13 | Son | — | Massachusetts |
| 66 | Edmond Dziadul | 12 | Son | — | Massachusetts |
| 67 | John Dziadul | 5 | Son | — | Massachusetts |
| 68 | Joan Dziadul | 5 | Daughter | — | Massachusetts |
| 69 | Dorothy Dziadul | 3 | Daughter | — | Massachusetts |
| 70 | Florence Dziadul | 1 | Daughter | — | Massachusetts |
| 71 | Joseph Pietrewicz | 50 | Head | Polisher | Poland |
| 72 | Michalina Pietrewicz | 45 | Wife | — | Poland |
| 73 | Edward Pietrewicz | 15 | Son | — | Massachusetts |
| 74 | Thadeus Pietrewicz | 13 | Son | — | Massachusetts |
| 75 | Theresa Pietrewicz | 11 | Daughter | — | Massachusetts |
| 76 | Benjamin Surozinski | 50 | Boarder | Machinist | Poland |
| 77 | Stanislaus Mysliwiec | 45 | Head | Second Hand Agent | Poland |
| 78 | Phylis Mysliwiec | 37 | Wife | — | Poland |
| 79 | Hedda Mysliwiec | 13 | Daughter | — | Massachusetts |
| 80 | John Mysliwiec | 11 | Son | — | Massachusetts |
Related Census Records
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)