ML
Mary Leahy — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Norfolk-County, Massachusetts
Our Model Tree links this Mary Leahy across the 1930 and 1940 US Censuses in Norfolk-County, Massachusetts (XGBoost, ~Confirmed) — first a daughter (b.~1916), then head of a 10-person household.
Age 24
b. ~1916
Female
Daughter
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Norfolk-County, Massachusetts |
| Surname | Leahy |
| Given Name | Mary E. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 24 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Town of Braintree |
| 1935 Residence (County) | Norfolk |
| Additional Details | |
| Highest Grade | H 2 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Township / Ward | Town Of Braintree |
| Est. Birth Year | ~1916 |
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.
10 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| William Leahy | Head | — | 55 | ~1885 |
| James Leahy | Son | — | 16 | ~1924 |
| Teresa Leahy | Daughter | — | 11 | ~1929 |
| George Leahy | Son | — | 20 | ~1920 |
| Thomas Leahy | Son | — | 14 | ~1926 |
| Alice Leahy | Daughter | — | 9 | ~1931 |
| Helen Leahy | Daughter | — | 5 | ~1935 |
| Mary Leahy | Daughter | — | 24 | ~1916 |
| Rose Leahy | Spouse | — | 51 | ~1889 |
| Kathleen Leahy | Daughter | — | 18 | ~1922 |
Census Appearances
1930
Norfolk, Massachusetts
Daughter, age 14
Norfolk, Massachusetts · implied b. ~1916 — 13 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leahy |
| Given Name | Mary E. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 14 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Norfolk-County, Massachusetts
Daughter, age 24
Norfolk-County, Massachusetts · implied b. ~1916 — 10 household members
| Surname | Leahy |
| Given Name | Mary E. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 24 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Town of Braintree |
| 1935 Residence (County) | Norfolk |
| Highest Grade | H 2 |
| 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 Mary Leahy across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Leahy
Daughter · 1940 · age 24 · b. ~1916 · Massachusetts
★ You are viewing this record
Sibling
Kathleen Leahy
Sibling · 1940 · age 18
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Thomas Leahy
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Teresa Leahy
Sibling · 1940 · age 11
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Helen Leahy
Sibling · 1940 · age 5
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Leahy
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Alice Leahy
Sibling · 1940 · age 9
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
George Leahy
Sibling · 1940 · age 20
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 — Norfolk-County, Massachusetts
Open full size
1940 US Federal Census — Norfolk-County, Massachusetts
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01624-00251)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Betty A. Watts | 10 | Daughter | — | Massachusetts |
| 2 | Shirley F. Watts | 10 | Daughter | — | Massachusetts |
| 3 | Delphine Watts | 69 | Mother-in-law | — | Massachusetts |
| 4 | William F. B. Leahy | 55 | Head | Welder | Massachusetts |
| 5 | Rose J. Leahy | 51 | Wife | — | Massachusetts |
| 6 | Mary E. Leahy THIS PERSON | 24 | Daughter | — | Massachusetts |
| 7 | George F. Leahy | 20 | Son | — | Massachusetts |
| 8 | Kathleen E. Leahy | 18 | Daughter | — | Massachusetts |
| 9 | James B. Leahy | 16 | Son | — | Massachusetts |
| 10 | Thomas R. Leahy | 14 | Son | — | Massachusetts |
| 11 | Teresa M. Leahy | 11 | Daughter | — | Massachusetts |
| 12 | Alice A. Leahy | 9 | Daughter | — | Massachusetts |
| 13 | Helen A. Leahy | 5 | Daughter | — | Massachusetts |
| 14 | Robert B. Reader | 58 | Head | Carpenter | England |
| 15 | Lillian Reader | 55 | Wife | — | Massachusetts |
| 16 | Robert B. Reader | 19 | Son | Helper | Massachusetts |
| 17 | Percival H. L. Dunn | 36 | Head | Painter | Massachusetts |
| 18 | Ruth A. Dunn | 39 | Wife | — | Massachusetts |
| 19 | George H. Dunn | 15 | Son | — | Massachusetts |
| 20 | Carroll J. Goudrey | 43 | Head | Garage Man | Nova Scotia |
| 21 | Ann V. B. Goudrey | 41 | Wife | — | Nova Scotia |
| 22 | Elsie M. Goudrey | 14 | Daughter | — | Massachusetts |
| 23 | Jean M. Goudrey | 12 | Daughter | — | Massachusetts |
| 24 | Augusta F. Henrich | 44 | Head | Salesgirl | New York |
| 25 | Claire F. Henrich | 21 | Daughter | Typist | Massachusetts |
| 26 | Antoinette M. Henrich | 18 | Daughter | — | Massachusetts |
| 27 | William B. Henrich | 14 | Son | — | Massachusetts |
| 28 | David R. Henrich | 13 | Son | — | Massachusetts |
| 29 | Michael J. Kelley | 31 | Head | Pipefitter | Massachusetts |
| 30 | Mary Kelley | 30 | Wife | — | Massachusetts |
| 31 | Joan M. Kelley | 7 | Daughter | — | Massachusetts |
| 32 | Janette L. Kelley | 4 | Daughter | — | Massachusetts |
| 33 | Joseph F. Kelley | 3 | Son | — | Massachusetts |
| 34 | William F. Fitzgerald | 33 | Cousin | Longshoreman | Rhode Island |
| 35 | Alexander L'Angle | 50 | Head | Stonemason | Canada-French |
| 36 | Annie L'Angle | 51 | Wife | — | Canada-French |
| 37 | Thomas W. L'Angle | 22 | Son | Painter | Massachusetts |
| 38 | John P. L'Angle | 21 | Son | — | Massachusetts |
| 39 | Joseph L. L'Angle | 17 | Son | New Worker | Massachusetts |
| 40 | Helen L. L'Angle | 15 | 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)