JC
John Cahill — 1940 US Census Record
Model Tree available1940 United States Federal Census · Suffolk-County, Massachusetts
Our Model Tree links this John Cahill across the 1920, 1930 and 1940 US Censuses in Suffolk-County, Massachusetts (XGBoost, ~Confirmed), with identified parents Ellen & Daniel — first a son (b.~1910), then head of a 4-person household.
Age 30
b. ~1910
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Suffolk-County, Massachusetts |
| Surname | Cahill |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 30 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston |
| 1935 Residence (County) | Suffolk |
| Additional Details | |
| Occupation | salesman |
| Industry | autom. factory |
| Class of Worker | PW |
| Hours Worked | 50 |
| Income (1939) | 2169 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Salesman |
| Township / Ward | Boston |
| Est. Birth Year | ~1910 |
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.
4 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Ellen Cahill | Spouse | — | 57 | ~1883 |
| Daniel Cahill | Head | — | 54 | ~1886 |
| John Cahill | Son | — | 30 | ~1910 |
| Helen Cahill | Daughter | — | 21 | ~1919 |
Census Appearances
1920
Suffolk, Massachusetts
Other, age 10
Suffolk, Massachusetts · implied b. ~1910 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Cahill |
| Given Name | John |
| Relationship to Head | Stepson |
| Sex | M |
| Color / Race | White |
| Age | 10 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1930
Suffolk, Massachusetts
Other, age 20
Suffolk, Massachusetts · implied b. ~1910 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Cahill |
| Given Name | John |
| Relationship to Head | Step-son |
| Sex | M |
| Color / Race | White |
| Age | 20 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Occupation | Pressman |
| Industry | Lithograph |
| Class of Worker | W |
| Can Read/Write | Yes |
| Veteran | No |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Suffolk-County, Massachusetts
Son, age 30
Suffolk-County, Massachusetts · implied b. ~1910 — 4 household members
| Surname | Cahill |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 30 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston |
| 1935 Residence (County) | Suffolk |
| Occupation | salesman |
| Industry | autom. factory |
| Class of Worker | PW |
| Hours Worked | 50 |
| Income (1939) | 2169 |
| Highest Grade | H 4 |
| 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 Cahill across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: mother Ellen Cahill (~0.92 confidence) and father Daniel Cahill (~0.92 confidence). The pedigree spans 1 generation with 2 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Mother
Ellen Cahill
b. ~1883
Source mother
● Household
· direct · ~0.92
Father
Daniel Cahill
b. ~1886
Source father
● Household
· direct · ~0.92
This person
Anchor record
John Cahill
Son · 1940 · age 30 · b. ~1910 · Massachusetts
★ You are viewing this record
Sibling
Helen Cahill
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
40 people indexed on this census page (nara:1940:m-t0627-01675-00346)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | William D Gaston | 48 | Head | Cook | Massachusetts |
| 42 | Mary H Gaston | 38 | Wife | Clerk | Massachusetts |
| 43 | Elizabeth Gaston | 16 | Daughter | School | New York |
| 44 | Edward Finnegan | 40 | Head | Clerk | Massachusetts |
| 45 | Della B Finnegan | 39 | Wife | Housewife | Massachusetts |
| 46 | Anna Donelin | 69 | Mother in law | — | Massachusetts |
| 47 | Garrett Farrell | 39 | Head | Police Officer | Massachusetts |
| 48 | Alice Farrell | 41 | Wife | Housework | Massachusetts |
| 49 | Albin Lundbohm | 48 | Lodger | — | Massachusetts |
| 50 | John Mcdonough | 47 | Head | Store Manager | Ireland |
| 51 | Julia B Mcdonough | 36 | Wife | Housework | Ireland |
| 52 | Mary Mcdonough | 7 | Daughter | — | Massachusetts |
| 53 | Joan Mcdonough | 5 | Daughter | — | Massachusetts |
| 54 | Charles H Fitch | 48 | Head | Custodian | Massachusetts |
| 55 | Mary E Fitch | 44 | Wife | Housewife | Massachusetts |
| 56 | Lois H Fitch | 17 | Daughter | School | Massachusetts |
| 57 | Ruth D Fitch | 14 | Daughter | School | Massachusetts |
| 58 | Margaret M Fitch | 64 | Mother | — | Massachusetts |
| 59 | Daniel Cahill | 54 | Head | Laborer | Ireland |
| 60 | Ellen B Cahill | 57 | Wife | Housewife | Ireland |
| 61 | John Cahill THIS PERSON | 30 | Son | Salesman | Massachusetts |
| 62 | Helen Cahill | 21 | Daughter | Clerk | Massachusetts |
| 63 | Daniel H Milligan | 42 | Head | Truck Driver | Massachusetts |
| 64 | Helen B Milligan | 40 | Wife | Housewife | Massachusetts |
| 65 | Alexander Milligan | 19 | Son | Molder Helper | Massachusetts |
| 66 | Edna Milligan | 17 | Daughter | New Worker | Massachusetts |
| 67 | Doris Milligan | 16 | Daughter | School | Massachusetts |
| 68 | Helen Milligan | 15 | Daughter | School | Massachusetts |
| 69 | Daniel Jr Milligan | 14 | Son | School | Massachusetts |
| 70 | Robert Milligan | 12 | Son | — | Massachusetts |
| 71 | Claire Milligan | 6 | Daughter | — | Massachusetts |
| 72 | James Milligan | 2 | Son | — | Massachusetts |
| 73 | Herbert Skinner | 57 | Head | Night Watchman | Massachusetts |
| 74 | Gertrude Skinner | 58 | Wife | Housewife | Massachusetts |
| 75 | Charles H Skinner | 61 | Brother | Clerk | Massachusetts |
| 76 | Frank E Derner | 51 | Head | Fountain Pen | Massachusetts |
| 77 | Louise C Derner | 50 | Wife | Housewife | Massachusetts |
| 78 | Pauline M Derner | 12 | Daughter | — | Massachusetts |
| 79 | Henry L Derner | 9 | Son | — | Massachusetts |
| 80 | Joseph Leary | 44 | Head | Salesman | Massachusetts |
Pedigree Summary
John + 1 sibling
Gen 1 · 2 parents
~0.92
Max depth 4 (1900–1950 window)
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)