JL
John Leahy — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Suffolk-County, Massachusetts
Our Model Tree links this John Leahy across the 1930 and 1940 US Censuses in Suffolk-County, Massachusetts (XGBoost, ~Confirmed) — first a son (b.~1915), then head of a 9-person household.
Age 25
b. ~1915
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Suffolk-County, Massachusetts |
| Surname | Leahy |
| Given Name | John F. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston |
| 1935 Residence (County) | Suffolk |
| Additional Details | |
| Occupation | Accountant |
| Industry | Accounting Company |
| Class of Worker | PW |
| Hours Worked | 38 |
| Income (1939) | 1010 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same House |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Accountant |
| Township / Ward | Boston |
| 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.
9 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Margaret Leahy | Daughter | — | 21 | ~1919 |
| Edward Leahy | Son | — | 13 | ~1927 |
| Joseph Leahy | Son | — | 20 | ~1920 |
| Nellie Leahy | Spouse | — | 50 | ~1890 |
| Eleanore Leahy | Daughter | — | 8 | ~1932 |
| John Leahy | Son | — | 25 | ~1915 |
| William Leahy | Son | — | 12 | ~1928 |
| David Leahy | Head | — | 55 | ~1885 |
| Esther Leahy | Daughter | — | 15 | ~1925 |
Census Appearances
1930
Suffolk, Massachusetts
Son, age 14
Suffolk, Massachusetts · implied b. ~1916 — 10 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leahy |
| Given Name | John F |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 14 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Suffolk-County, Massachusetts
Son, age 25
Suffolk-County, Massachusetts · implied b. ~1915 — 9 household members
| Surname | Leahy |
| Given Name | John F. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston |
| 1935 Residence (County) | Suffolk |
| Occupation | Accountant |
| Industry | Accounting Company |
| Class of Worker | PW |
| Hours Worked | 38 |
| Income (1939) | 1010 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same House |
| 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 25 · b. ~1915 · Massachusetts
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Sibling
Eleanore Leahy
Sibling · 1940 · age 8
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Edward Leahy
Sibling · 1940 · age 13
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Joseph Leahy
Sibling · 1940 · age 20
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
William Leahy
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Esther Leahy
Sibling · 1940 · age 15
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Margaret Leahy
Sibling · 1940 · age 21
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 — Suffolk-County, Massachusetts
Open full size
1940 US Federal Census — Suffolk-County, Massachusetts
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01672-00344)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Morris Alper | 64 | Head | — | Poland |
| 2 | Rachel Alper | 67 | Wife | — | Poland |
| 3 | Irene Alper | 24 | Daughter | Hairdresser | Massachusetts |
| 4 | Louis Hurvitz | 40 | Head | Variety Store | Poland |
| 5 | Sarah R. Hurvitz | 32 | Wife | Clerk | Poland |
| 6 | Evelyn H. Hurvitz | 15 | Daughter | — | Massachusetts |
| 7 | Hazel E. Hurvitz | 10 | Daughter | — | Massachusetts |
| 8 | David D. Leahy | 55 | Head | Fireman | Irish Free State |
| 9 | Nellie Leahy | 50 | Wife | — | Irish Free State |
| 10 | John F. Leahy THIS PERSON | 25 | Son | Accountant | Massachusetts |
| 11 | Margaret M. Leahy | 21 | Daughter | Typist | Massachusetts |
| 12 | Joseph D. Leahy | 20 | Son | Machinist | Massachusetts |
| 13 | Esther Leahy | 15 | Daughter | — | Massachusetts |
| 14 | Edward T. Leahy | 13 | Son | — | Massachusetts |
| 15 | William V. Leahy | 12 | Son | — | Massachusetts |
| 16 | Eleanore B. Leahy | 8 | Daughter | — | Massachusetts |
| 17 | Bernard Finn | 72 | Head | — | Poland |
| 18 | Frederick Finn | 47 | Son | Shipper | Massachusetts |
| 19 | Jacob Weiser | 40 | Son-in-law | Cloth Inspector | Poland |
| 20 | Ruth Weiser | 21 | Daughter | — | Massachusetts |
| 21 | Lester M. Weiser | 0 | Grandson | — | Massachusetts |
| 22 | Sadie Weiser | 30 | Lodger | Sorter | Massachusetts |
| 23 | Joseph Abrams | 49 | Head | Novel Painter | Poland |
| 24 | Emma Abrams | 43 | Wife | — | Poland |
| 25 | Harold Abrams | 22 | Son | Recreation Attendant | Massachusetts |
| 26 | Edith A. Abrams | 18 | Daughter | Dressmaker Apprentice | Massachusetts |
| 27 | Martha A. Davies | 24 | Law | Finisher Bottling | Massachusetts |
| 28 | Harry Wolk | 52 | Head | — | Massachusetts |
| 29 | Ida Wolk | 33 | Wife | — | Massachusetts |
| 30 | Anna Wolk | 6 | Daughter | — | Massachusetts |
| 31 | Albert Wolk | 5 | Son | — | Massachusetts |
| 32 | Aaron Wolk | 85 | Father | — | Poland |
| 33 | Harry Dobkin | 49 | Head | Chore Man | Massachusetts |
| 34 | Frances E. Dobkin | 46 | Wife | — | Poland |
| 35 | Selma C. Dobkin | 18 | Daughter | — | Massachusetts |
| 36 | Melvin E. Dobkin | 14 | Son | — | Massachusetts |
| 37 | Howard L. Dobkin | 10 | Son | — | Massachusetts |
| 38 | John Pepe | 58 | Head | Tailor | Italy |
| 39 | Maria Pepe | 44 | Wife | — | Italy |
| 40 | Joseph S. Pepe | 28 | Son | Commercial Artist | Italy |
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)