JL
John Leahy — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Middlesex-County, Massachusetts
Our Model Tree links this John Leahy across the 1930 and 1940 US Censuses in Middlesex-County, Massachusetts (XGBoost, ~Confirmed) — first a head (b.~1885), then head of a 5-person household.
Age 55
b. ~1885
Male
Head
Born: Massachusetts
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Middlesex-County, Massachusetts |
| Surname | Leahy |
| Given Name | John M. |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 55 |
| Marital Status | Married |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Middlesex |
| 1935 Residence (County) | Middlesex |
| Additional Details | |
| Occupation | Clerk |
| Class of Worker | PW |
| Hours Worked | 3 |
| Income (1939) | 180 |
| Highest Grade | No 8 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Clerk |
| Township / Ward | Middlesex |
| Est. Birth Year | ~1885 |
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.
5 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Francis Leahy | Son | — | 27 | ~1913 |
| Eva Leahy | Spouse | — | 57 | ~1883 |
| John Leahy | Head | — | 55 | ~1885 |
| Eva Leahy | Daughter | — | 22 | ~1918 |
| Helen Leahy | Daughter | — | 20 | ~1920 |
Census Appearances
1930
Middlesex, Massachusetts
Head, age 44
Middlesex, Massachusetts · implied b. ~1886 — 7 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leahy |
| Given Name | John M. |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 44 |
| Marital Status | Married |
| Birthplace | Massachusetts |
| Age at First Marriage | 20 |
| Father's Birthplace | Irish Free State |
| Mother's Birthplace | Irish Free State |
| Occupation | Mechanic |
| Industry | Garage |
| Class of Worker | W |
| Can Read/Write | Yes |
| Home Owned/Rented | R |
| Home Value / Rent | 16 |
| Radio Set | R |
| Veteran | No |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Middlesex-County, Massachusetts
Head, age 55
Middlesex-County, Massachusetts · implied b. ~1885 — 5 household members
| Surname | Leahy |
| Given Name | John M. |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 55 |
| Marital Status | Married |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Middlesex |
| 1935 Residence (County) | Middlesex |
| Occupation | Clerk |
| Class of Worker | PW |
| Hours Worked | 3 |
| Income (1939) | 180 |
| Highest Grade | No 8 |
| 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.
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This person
Anchor record
John Leahy
Head · 1940 · age 55 · b. ~1885 · Massachusetts
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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 — Middlesex-County, Massachusetts
Open full size
1940 US Federal Census — Middlesex-County, Massachusetts
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01612-00071)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Nancy Emerald | 3 | — | — | Massachusetts |
| 42 | John Mchugh | 52 | Head | Longshoreman | Eire |
| 43 | Mary Mchugh | 55 | Wife | — | Newfoundland |
| 44 | Michael Mchugh | 34 | Son | Operator | Massachusetts |
| 45 | Robert Downes | 35 | Head | Shipper | Massachusetts |
| 46 | Marian Downes | 34 | Wife | — | Massachusetts |
| 47 | Mary Downes | 73 | Mother | — | Canada English |
| 48 | George Parker | 56 | Head | Plumber | Newfoundland |
| 49 | Margaret Parker | 55 | Wife | — | Canada English |
| 50 | Patricia Parker | 26 | Daughter | Saleslady | Canada English |
| 51 | Lydia Parker | 21 | Daughter | Teacher | Massachusetts |
| 52 | Thomas Parker | 20 | Son | Plumber'S Helper | Massachusetts |
| 53 | George Parker | 15 | Son | — | Massachusetts |
| 54 | Herbert Frost | 40 | Head | Foreman | Maine |
| 55 | Amy Frost | 33 | Wife | — | Massachusetts |
| 56 | Barbara Frost | 11 | Daughter | — | Massachusetts |
| 57 | Ralph Frost | 10 | Son | — | Massachusetts |
| 58 | Jane Frost | 7 | Daughter | — | Massachusetts |
| 59 | Helene Frost | 5 | Daughter | — | Massachusetts |
| 60 | Walter Frost | 4 | Son | — | Massachusetts |
| 61 | Virginia Frost | 2 | Daughter | — | Massachusetts |
| 62 | John M. Leahy THIS PERSON | 55 | Head | Clerk | Massachusetts |
| 63 | Eva M. Leahy | 57 | Wife | — | Massachusetts |
| 64 | Francis Leahy | 27 | Son | Shoemaker | Massachusetts |
| 65 | Eva Leahy | 22 | Daughter | Salesgirl | Massachusetts |
| 66 | Helen Leahy | 20 | Daughter | — | Massachusetts |
| 67 | Louis Colarusso | 55 | Head | Nickelplater | Italy |
| 68 | Anna Colarusso | 49 | Wife | — | Massachusetts |
| 69 | John Simmons | 30 | Head | — | — |
| 70 | Genevieve Simmons | 28 | Wife | — | — |
| 71 | Alma N. Stone | 49 | Head | Dressmaker | Massachusetts |
| 72 | Barbara Stone | 20 | Daughter | — | Massachusetts |
| 73 | Lester D. Stone | 19 | Son | Printer | Massachusetts |
| 74 | Gustaf Palm | 53 | Head | Carpenter | Sweden |
| 75 | Adga Palm | 54 | Wife | — | Sweden |
| 76 | John Palm | 14 | Son | — | Massachusetts |
| 77 | Warren F. Lee | 55 | Head | Treasurer | Massachusetts |
| 78 | Myrtle F. Lee | 47 | Wife | — | Maine |
| 79 | Clyde F. Lee | 30 | Son | Salesman | Massachusetts |
| 80 | Dorothy Cross | 23 | Daughter | — | Massachusetts |
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)