MC
Mary Cahill — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cerro-Gordo-County, Iowa
Our Model Tree links this Mary Cahill across the 1930 and 1940 US Censuses in Cerro-Gordo-County, Iowa (XGBoost, ~Confirmed) — first a daughter (b.~1925), then head of a 11-person household.
Age 15
b. ~1925
Female
Daughter
Born: Iowa
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Cerro-Gordo-County, Iowa |
| Surname | Cahill |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 15 |
| Marital Status | Single |
| Birthplace | Iowa |
| 1935 Residence (City) | Rockwell Town |
| 1935 Residence (County) | Cerro Gordo |
| Additional Details | |
| Income (1939) | 0 |
| Highest Grade | H-2 |
| 1935 Residence | Same place |
| Birth State | Iowa |
| Birth Country | United States |
| Birthplace (normalized) | iowa |
| Township / Ward | Rockwell Town |
| Est. Birth Year | ~1925 |
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.
11 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Edward Cahill | Son | — | 8 | ~1932 |
| Bertina Cahill | Daughter | — | 3 | ~1937 |
| Martin Cahill | Son | — | 16 | ~1924 |
| Mary Cahill | Daughter | — | 15 | ~1925 |
| Michael Cahill | Son | — | 6 | ~1934 |
| Patricia Cahill | Daughter | — | 5 | ~1935 |
| Gerald Cahill | Son | — | 13 | ~1927 |
| Patrick Cahill | Son | — | 11 | ~1929 |
| John Cahill | Head | — | 42 | ~1898 |
| Ella Cahill | Spouse | — | 40 | ~1900 |
| Helen Cahill | Daughter | — | 9 | ~1931 |
Census Appearances
1930
Cerro Gordo, …
Daughter, age 5
Cerro Gordo, Iowa · implied b. ~1925 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Cahill |
| Given Name | Mary Lou |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 5 |
| Marital Status | Single |
| Birthplace | Iowa |
| Father's Birthplace | Iowa |
| Mother's Birthplace | Iowa |
| Birth State | Iowa |
| Birth Country | United States |
| Birthplace (normalized) | iowa |
1940
Cerro-Gordo-County, Iowa
Daughter, age 15
Cerro-Gordo-County, Iowa · implied b. ~1925 — 11 household members
| Surname | Cahill |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 15 |
| Marital Status | Single |
| Birthplace | Iowa |
| 1935 Residence (City) | Rockwell Town |
| 1935 Residence (County) | Cerro Gordo |
| Income (1939) | 0 |
| Highest Grade | H-2 |
| 1935 Residence | Same place |
| Birth State | Iowa |
| Birth Country | United States |
| Birthplace (normalized) | iowa |
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 15 · b. ~1925 · Iowa
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Sibling
Helen Cahill
Sibling · 1940 · age 9
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Edward Cahill
Sibling · 1940 · age 8
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Bertina Cahill
Sibling · 1940 · age 3
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Patricia Cahill
Sibling · 1940 · age 5
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Michael Cahill
Sibling · 1940 · age 6
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Patrick Cahill
Sibling · 1940 · age 11
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Martin Cahill
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Gerald Cahill
Sibling · 1940 · age 13
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 — Cerro-Gordo-County, Iowa
Open full size
1940 US Federal Census — Cerro-Gordo-County, Iowa
Page Contents
39 people indexed on this census page (nara:1940:m-t0627-01146-00219)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | James O. Kielty | 79 | Head | — | Iowa |
| 42 | Christina Kielty | 71 | Wife | — | Illinois |
| 43 | E. S. Roland | 63 | Head | — | Iowa |
| 44 | Mellina Roland | 56 | Wife | — | Nebraska |
| 45 | Joseph Burke | 53 | Head | Painter | New York |
| 46 | Carrie Burke | 37 | Wife | — | Iowa |
| 47 | Mary Burke | 11 | Daughter | — | Iowa |
| 48 | Leo Burke | 10 | Son | — | Iowa |
| 49 | Alfred Burke | 7 | Son | — | Iowa |
| 50 | Joan Burke | 6 | Daughter | — | Iowa |
| 51 | Jean Burke | 6 | Daughter | — | Iowa |
| 52 | James Burke | 5 | Son | — | Iowa |
| 54 | Henry Miller | 59 | Head | Manual Labor | Germany |
| 55 | Anna Miller | 49 | Wife | — | Germany |
| 56 | Gladys Miller | 20 | Daughter | Teacher | Iowa |
| 57 | John Cahill | 42 | Head | Manager | Iowa |
| 58 | Ella Cahill | 40 | Wife | — | Iowa |
| 59 | Martin Cahill | 16 | Son | — | Iowa |
| 60 | Mary Cahill THIS PERSON | 15 | Daughter | — | Iowa |
| 61 | Gerald Cahill | 13 | Son | — | Iowa |
| 62 | Patrick Cahill | 11 | Son | — | Iowa |
| 63 | Helen Cahill | 9 | Daughter | — | Iowa |
| 64 | Edward Cahill | 8 | Son | — | Iowa |
| 65 | Michael Cahill | 6 | Son | — | Iowa |
| 66 | Patricia Cahill | 5 | Daughter | — | Iowa |
| 67 | Bertina Cahill | 3 | Daughter | — | Iowa |
| 68 | J. F. Fitzgerald | 42 | Head | Automobile Salesman | Illinois |
| 69 | Irene Fitzgerald | 42 | Wife | — | Iowa |
| 70 | J. F. Jr. Fitzgerald | 18 | Son | Manual Labor | Iowa |
| 71 | Irving Fitzgerald | 16 | Son | — | Iowa |
| 72 | Geraldine Fitzgerald | 14 | Daughter | — | Iowa |
| 73 | Leo Pat Fitzgerald | 12 | Son | — | Iowa |
| 74 | Jackie Fitzgerald | 10 | Son | — | Iowa |
| 75 | Ann Marie Fitzgerald | 5 | Daughter | — | Iowa |
| 76 | Kay Fitzgerald | 1 | Daughter | — | Iowa |
| 77 | N. C. Eye | 62 | Head | — | Illinois |
| 78 | Elizabeth Eye | 65 | Wife | — | Iowa |
| 79 | Verle Guidler | 40 | Head | — | Iowa |
| 80 | Irene Guidler | 43 | Wife | — | Ohio |
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)