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.~1923), then head of a 6-person household.
Age 17
b. ~1923
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Suffolk-County, Massachusetts |
| Surname | Leahy |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 17 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston city |
| 1935 Residence (County) | Suffolk |
| Additional Details | |
| Occupation | clerk |
| Industry | W.P.A. |
| Class of Worker | GW |
| Hours Worked | 32 |
| Income (1939) | 1103 |
| Highest Grade | H-1 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Clerk |
| Township / Ward | Boston 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.
6 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| John Leahy | Son | — | 17 | ~1923 |
| Margaret Leahy | Daughter | — | 21 | ~1919 |
| Julia Leahy | Daughter | — | 23 | ~1917 |
| William Leahy | Son | — | 19 | ~1921 |
| Michael Leahy | Head | — | 51 | ~1889 |
| Margaret Leahy | Spouse | — | 56 | ~1884 |
Census Appearances
1930
Suffolk, Massachusetts
Son, age 7
Suffolk, Massachusetts · implied b. ~1923 — 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 | 7 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Irish Free State |
| Mother's Birthplace | Irish Free State |
| Occupation | Student |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Suffolk-County, Massachusetts
Son, age 17
Suffolk-County, Massachusetts · implied b. ~1923 — 6 household members
| Surname | Leahy |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 17 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston city |
| 1935 Residence (County) | Suffolk |
| Occupation | clerk |
| Industry | W.P.A. |
| Class of Worker | GW |
| Hours Worked | 32 |
| Income (1939) | 1103 |
| Highest Grade | H-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 17 · b. ~1923 · Massachusetts
★ You are viewing this record
Sibling
William Leahy
Sibling · 1940 · age 19
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Julia Leahy
Sibling · 1940 · age 23
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
34 people indexed on this census page (nara:1940:m-t0627-01659-00292)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Mary Lord | 27 | Wife | — | Massachusetts |
| 42 | Marjorie Lord | 7 | Daughter | — | Massachusetts |
| 43 | Patricia Lord | 3 | Daughter | — | Massachusetts |
| 44 | William Lord | 0 | Son | — | Massachusetts |
| 45 | James Mcgrath | 27 | Head | Machine Filler | Massachusetts |
| 46 | Rita Mcgrath | 23 | Wife | — | Massachusetts |
| 47 | Patrick Conroy | 36 | Head | Laborer | Eire |
| 48 | Mary Conroy | 36 | Wife | — | Massachusetts |
| 49 | Mary Conroy | 7 | Daughter | — | Massachusetts |
| 50 | David Conroy | 1 | Son | — | Massachusetts |
| 51 | Dennis Doherty | 42 | Head | Railway Clerk | Massachusetts |
| 52 | Catherine Doherty | 38 | Wife | — | Eire |
| 53 | Francis Doherty | 10 | Son | — | Massachusetts |
| 54 | Patricia Doherty | 6 | Daughter | — | Massachusetts |
| 55 | Anne Doherty | 1 | Daughter | — | Massachusetts |
| 56 | Richard Stapleton | 34 | Head | Policeman | Massachusetts |
| 57 | Mary Stapleton | 29 | Wife | — | Rhode Island |
| 58 | Richard Stapleton | 6 | Son | — | Massachusetts |
| 59 | Robert Stapleton | 3 | Son | — | Massachusetts |
| 60 | Michael Leahy | 51 | Head | Bartender | Eire |
| 61 | Margaret Leahy | 56 | Wife | — | Eire |
| 62 | Julia Leahy | 23 | Daughter | Telephone Operator | Massachusetts |
| 63 | Margaret Leahy | 21 | Daughter | Candy Packer | Massachusetts |
| 64 | William Leahy | 19 | Son | Candy Packer | Massachusetts |
| 65 | John Leahy THIS PERSON | 17 | Son | Clerk | Massachusetts |
| 66 | John Norton | 41 | Head | Supervisor | Massachusetts |
| 67 | Agnes Norton | 37 | Wife | — | Massachusetts |
| 68 | Mary Norton | 17 | Daughter | — | Massachusetts |
| 69 | John Jr. Norton | 15 | Son | — | Massachusetts |
| 70 | Frances Norton | 13 | Daughter | — | Massachusetts |
| 71 | Robert Norton | 3 | Son | — | Massachusetts |
| 72 | Anne Norton | 0 | Daughter | — | Massachusetts |
| 73 | Rose Norton | 73 | Mother | — | Massachusetts |
| 74 | Rose Norton | 44 | Sister | — | 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)