JL
John Leahy — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Hampden-County, Massachusetts
Our Model Tree links this John Leahy across the 1930 and 1940 US Censuses in Hampden-County, Massachusetts (XGBoost, ~Confirmed) — first a son (b.~1928), then head of a 5-person household.
Age 12
b. ~1928
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Hampden-County, Massachusetts |
| Surname | Leahy |
| Given Name | John W. |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | West Springfield |
| 1935 Residence (County) | Hampden |
| Additional Details | |
| Industry | 0 |
| Class of Worker | No |
| Highest Grade | No 7 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Township / Ward | West Springfield |
| Est. Birth Year | ~1928 |
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 |
|---|---|---|---|---|
| John Leahy | Son | — | 12 | ~1928 |
| Thomas Leahy | Son | — | 14 | ~1926 |
| Margaret Leahy | Daughter | — | 10 | ~1930 |
| Pauline Leahy | Spouse | — | 39 | ~1901 |
| Thomas Leahy | Head | — | 39 | ~1901 |
Census Appearances
1930
Hampden, Massachusetts
Son, age 2
Hampden, Massachusetts · implied b. ~1928 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leahy |
| Given Name | John W. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 2 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | United States |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Hampden-County, Massachusetts
Son, age 12
Hampden-County, Massachusetts · implied b. ~1928 — 5 household members
| Surname | Leahy |
| Given Name | John W. |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | West Springfield |
| 1935 Residence (County) | Hampden |
| Industry | 0 |
| Class of Worker | No |
| Highest Grade | No 7 |
| 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 12 · b. ~1928 · Massachusetts
★ You are viewing this record
Sibling
Thomas Leahy
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Margaret Leahy
Sibling · 1940 · age 10
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 — Hampden-County, Massachusetts
Open full size
1940 US Federal Census — Hampden-County, Massachusetts
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01598-00779)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Mattie Pease | 81 | wife | — | Massachusetts |
| 2 | Helen S. Pease | 44 | daughter | Secretary | Massachusetts |
| 3 | Thomas Sullivan | 28 | head | Blade Operator | Massachusetts |
| 4 | Dorothy Sullivan | 26 | wife | — | Massachusetts |
| 5 | William Sullivan | 3 | son | 0 | Massachusetts |
| 6 | Thomas Jr. Sullivan | 1 | son | 0 | Massachusetts |
| 7 | Herbert F. Hollister | 20 | head | Apprentice Machinist | Massachusetts |
| 8 | Mary M. Hollister | 52 | mother | — | Massachusetts |
| 9 | Thomas J. Leahy | 39 | head | Laborer | Massachusetts |
| 10 | Pauline Leahy | 39 | wife | — | Massachusetts |
| 11 | Thomas J. Jr. Leahy | 14 | son | — | Massachusetts |
| 12 | John W. Leahy THIS PERSON | 12 | son | — | Massachusetts |
| 13 | Margaret S. Leahy | 10 | daughter | — | Massachusetts |
| 14 | Christian Pedersen | 58 | head | Cabinet Maker | Norway |
| 15 | Florence Pedersen | 22 | daughter | — | Massachusetts |
| 16 | Catherine Hatfield | 20 | daughter | — | Massachusetts |
| 17 | Charles L. Cahill | 37 | head | Truck Driver | Massachusetts |
| 18 | Dorothy Cahill | 29 | wife | — | Massachusetts |
| 19 | Arthur Cahill | 11 | son | — | Massachusetts |
| 20 | Elizabeth Cahill | 9 | daughter | — | Massachusetts |
| 21 | Raymond Cahill | 21 | nephew | Owner & Manager | Connecticut |
| 22 | Walter A. Lanfair | 51 | head | Owner Business | Massachusetts |
| 23 | Aldo F. Frisco | 27 | head | Manager | Massachusetts |
| 24 | Leila Frisco | 24 | wife | — | Massachusetts |
| 25 | Dora, Iris Frisco | 12 | daughter | 0 | Massachusetts |
| 26 | Frances Howlett | 69 | head | Box Maker | Massachusetts |
| 27 | William Smith | 33 | nephew | Truck Driver | Massachusetts |
| 28 | Minnie Whiteside | 35 | head | Household Aid | Connecticut |
| 29 | Kathleen Whiteside | 15 | daughter | — | Massachusetts |
| 30 | Fannie Mitchell | 69 | mother | — | Connecticut |
| 31 | Thomas J. Sullivan | 50 | head | Foreman | Massachusetts |
| 32 | Delia Sullivan | 56 | wife | — | Massachusetts |
| 33 | Josephine Sullivan | 30 | daughter | Binding Girl | Massachusetts |
| 34 | John Sullivan | 23 | son | New Worker | Massachusetts |
| 35 | Rose Sullivan | 14 | daughter | — | Massachusetts |
| 36 | Joseph Sullivan | 8 | grandson | — | Massachusetts |
| 37 | John Mcnamara | 4 | grandson | 0 | Massachusetts |
| 38 | Gertrude Johnson | 62 | head | Seamstress | Massachusetts |
| 39 | Leonard Johnson | 17 | son | — | Massachusetts |
| 40 | Oline Gouchie | 46 | head | — | 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)