MC
Mary Cahill — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Suffolk-County, Massachusetts
Our Model Tree links this Mary Cahill across the 1930 and 1940 US Censuses in Suffolk-County, Massachusetts (XGBoost, ~Confirmed) — first a daughter (b.~1928), then head of a 7-person household.
Age 12
b. ~1928
Female
Daughter
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Suffolk-County, Massachusetts |
| Surname | Cahill |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| Additional Details | |
| Highest Grade | No 8 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Township / Ward | Boston City |
| 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.
7 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Catherine Cahill | Daughter | — | 14 | ~1926 |
| Michael Cahill | Son | — | 16 | ~1924 |
| Barbara Cahill | Spouse | — | 41 | ~1899 |
| Patrick Cahill | Head | — | 43 | ~1897 |
| Patrick Cahill | Son | — | 7 | ~1933 |
| Mary Cahill | Daughter | — | 12 | ~1928 |
| Thomas Cahill | Son | — | 11 | ~1929 |
Census Appearances
1930
Suffolk, Massachusetts
Daughter, age 1
Suffolk, Massachusetts · implied b. ~1929 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Cahill |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 1 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Irish Free State |
| Mother's Birthplace | Massachusetts |
| Occupation | none |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Suffolk-County, Massachusetts
Daughter, age 12
Suffolk-County, Massachusetts · implied b. ~1928 — 7 household members
| Surname | Cahill |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| 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 Mary Cahill across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Cahill
Daughter · 1940 · age 12 · b. ~1928 · Massachusetts
★ You are viewing this record
Sibling
Catherine Cahill
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Michael Cahill
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Patrick Cahill
Sibling · 1940 · age 7
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Thomas Cahill
Sibling · 1940 · age 11
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
38 people indexed on this census page (nara:1940:m-t0627-01664-00172)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Bridget Molloy | 22 | Daughter | Packer | Massachusetts |
| 2 | Francis Molloy | 20 | Son | Laborer | Massachusetts |
| 3 | Rita Molloy | 18 | Daughter | — | Massachusetts |
| 4 | Helen Molloy | 15 | Daughter | — | Massachusetts |
| 5 | Samuel Hibbs | 50 | Head | Bldg. Wrecker | Newfoundland |
| 6 | Mary Hibbs | 72 | Wife | — | Newfoundland |
| 7 | James Hibbs | 36 | Son | Press Operator | Massachusetts |
| 8 | Carmella Bonanno | 44 | Head | — | Italy |
| 9 | Frank Bonanno | 23 | Son | Barber | Massachusetts |
| 10 | Lillian Bonanno | 18 | Daughter | Hair Dresser | Massachusetts |
| 11 | Mary Bonanno | 16 | Daughter | New Worker | Massachusetts |
| 12 | Joseph Bonanno | 14 | Son | — | Massachusetts |
| 13 | Nancy Bonanno | 10 | Daughter | — | Massachusetts |
| 16 | Patrick J. Shields | 66 | Head | Baker | Eire |
| 17 | Jane H. Shields | 26 | Niece | — | Eire |
| 18 | Thomas Healy | 65 | Lodger | Watchman | Massachusetts |
| 19 | Mary A. Soboleski | 24 | Lodger | Waitress | Massachusetts |
| 20 | Isaac Holler | 56 | Head | Bookbinder | Rhode Island |
| 21 | Rachelle Holler | 57 | Wife | — | New York |
| 22 | Bernard Skinner | 57 | Head | Watchman | Eire |
| 23 | Mary Skinner | 44 | Wife | — | Eire |
| 24 | Thomas Skinner | 16 | Son | — | Massachusetts |
| 25 | Grace Wilson | 50 | Head | Stitcher | Maine |
| 26 | Patrick Cahill | 43 | Head | Longshoreman | Eire |
| 27 | Barbara Cahill | 41 | Wife | — | Eire |
| 28 | Michael Cahill | 16 | Son | N.Y.A. | Massachusetts |
| 29 | Catherine Cahill | 14 | Daughter | — | Massachusetts |
| 30 | Mary Cahill THIS PERSON | 12 | Daughter | — | Massachusetts |
| 31 | Thomas Cahill | 11 | Son | — | Massachusetts |
| 32 | Patrick Jr. Cahill | 7 | Son | — | Massachusetts |
| 33 | Anton Sobiesched | 63 | Head | Cigar Maker | New York |
| 34 | Anna Sobiesched | 45 | Wife | — | Massachusetts |
| 35 | Daniel D. Sullivan | 51 | Head | Draw Tender | Massachusetts |
| 36 | Elizabeth Sullivan | 50 | Wife | — | Massachusetts |
| 37 | Elizabeth M. Sullivan | 14 | Daughter | — | Massachusetts |
| 38 | Mary F. Sullivan | 12 | Daughter | — | Massachusetts |
| 39 | Daniel J. Sullivan | 9 | Son | — | Massachusetts |
| 40 | Catherine J. Green | 21 | Niece | N.Y.A. Filing | 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)