JC
John Cahill — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Philadelphia-County, Pennsylvania
Our Model Tree links this John Cahill across the 1930 and 1940 US Censuses in Philadelphia-County, Pennsylvania (XGBoost, ~Confirmed) — first a son (b.~1922), then head of a 10-person household.
Age 18
b. ~1922
Male
Son
Born: Pennsylvania
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Philadelphia-County, Pennsylvania |
| Surname | Cahill |
| Given Name | John Jr |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 18 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| 1935 Residence (City) | Philadelphia |
| 1935 Residence (County) | Philadelphia |
| Additional Details | |
| Highest Grade | Hs 3 |
| 1935 Residence | Same Place |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
| Township / Ward | Philadelphia |
| Est. Birth Year | ~1922 |
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 John | Age | Birth yr |
|---|---|---|---|---|
| Alma Cahill | Daughter | — | 17 | ~1923 |
| Eugene Cahill | Son | — | 15 | ~1925 |
| Sarah Cahill | Daughter | — | 8 | ~1932 |
| Gerald Cahill | Son | — | 5 | ~1935 |
| Mary Cahill | Spouse | — | 42 | ~1898 |
| Marion Cahill | Daughter | — | 3 | ~1937 |
| Dorothy Cahill | Daughter | — | 10 | ~1930 |
| Mary Cahill | Daughter | — | 12 | ~1928 |
| John Cahill | Son | — | 18 | ~1922 |
| John Cahill | Head | — | 49 | ~1891 |
Census Appearances
1930
Delaware, Pennsylvania
Son, age 7
Delaware, Pennsylvania · implied b. ~1923 — 49 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Cahill |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 7 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| Father's Birthplace | Pennsylvania |
| Mother's Birthplace | England |
| Can Read/Write | Yes |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
1940
Philadelphia-County, Pennsylvania
Son, age 18
Philadelphia-County, Pennsylvania · implied b. ~1922 — 10 household members
| Surname | Cahill |
| Given Name | John Jr |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 18 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| 1935 Residence (City) | Philadelphia |
| 1935 Residence (County) | Philadelphia |
| Highest Grade | Hs 3 |
| 1935 Residence | Same Place |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
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 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
John Cahill
Son · 1940 · age 18 · b. ~1922 · Pennsylvania
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Sibling
Alma Cahill
Sibling · 1940 · age 17
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Eugene Cahill
Sibling · 1940 · age 15
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Dorothy Cahill
Sibling · 1940 · age 10
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Gerald Cahill
Sibling · 1940 · age 5
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Marion Cahill
Sibling · 1940 · age 3
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Sarah Cahill
Sibling · 1940 · age 8
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Mary Cahill
Sibling · 1940 · age 12
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 — Philadelphia-County, Pennsylvania
Open full size
1940 US Federal Census — Philadelphia-County, Pennsylvania
Page Contents
39 people indexed on this census page (nara:1940:m-t0627-03719-00012)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Fred Upchurch | 8 | Son | — | Pennsylvania |
| 2 | Margaret Upchurch | 5 | Daughter | — | Virginia |
| 3 | Dorothy Upchurch | 5 | Daughter | — | Virginia |
| 4 | Stanley Jr Upchurch | 3 | Son | — | Virginia |
| 5 | George Chambers | 46 | Head | Cook | Maryland |
| 6 | Elsie Chambers | 37 | Wife | — | Maryland |
| 7 | Sara Jenkins | 34 | Head | — | Pennsylvania |
| 8 | Mary Jenkins | 10 | Daughter | — | Pennsylvania |
| 9 | Jessie Jenkins | 6 | Daughter | — | Pennsylvania |
| 10 | John Sr Cahill | 49 | Head | Riveter | Pennsylvania |
| 11 | Mary Cahill | 42 | Wife | — | Pennsylvania |
| 12 | John Jr Cahill THIS PERSON | 18 | Son | — | Pennsylvania |
| 13 | Alma Cahill | 17 | Daughter | — | Pennsylvania |
| 14 | Eugene Cahill | 15 | Son | — | Pennsylvania |
| 15 | Mary E Cahill | 12 | Daughter | — | Pennsylvania |
| 16 | Dorothy Cahill | 10 | Daughter | — | Pennsylvania |
| 17 | Sarah Cahill | 8 | Daughter | — | Pennsylvania |
| 18 | Gerald Cahill | 5 | Son | — | Pennsylvania |
| 19 | Marion Cahill | 3 | Daughter | — | Pennsylvania |
| 20 | Benjamin Green | 48 | Head | Helper | South Carolina |
| 21 | Fred Green | 18 | Son | — | South Carolina |
| 22 | Leola Green | 16 | Daughter | — | Pennsylvania |
| 23 | Essie Green | 13 | Daughter | — | Pennsylvania |
| 24 | Samuel Green | 11 | Son | — | Pennsylvania |
| 25 | James Van Horn | 64 | Head | Motorman | Pennsylvania |
| 26 | Etta Van Horn | 60 | Wife | — | Pennsylvania |
| 27 | William Sr Mendel | 42 | Head | Garage Service Sta | New Jersey |
| 28 | Mary Mendel | 40 | Wife | — | Pennsylvania |
| 29 | William Jr Mendel | 15 | Son | — | Pennsylvania |
| 30 | Richard Mendel | 13 | Son | — | Pennsylvania |
| 31 | Mary L Mendel | 7 | Daughter | — | Pennsylvania |
| 32 | Thomas Grimes | 34 | Head | Barber | Virginia |
| 33 | Fannie Grimes | 32 | Wife | Beauty Shop | Virginia |
| 34 | Edward Grimes | 17 | Son | — | Virginia |
| 35 | Charles Grimes | 16 | Son | — | Virginia |
| 36 | Louise Brown | 16 | Niece | — | Virginia |
| 37 | Virginia Brown | 7 | Niece | — | Virginia |
| 38 | Ivory Brown | 30 | Brother | Maid | Virginia |
| 39 | Minor Helen Brown | 17 | Niece | — | Virginia |
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)