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John Mcdermott — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this John Mcdermott across the 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a son (b.~1917), then head of a 10-person household.
Age 23
b. ~1917
Male
Son
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | McDermott |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 23 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Additional Details | |
| Occupation | Helper |
| Industry | Meat Mkt |
| Class of Worker | PW |
| Hours Worked | 3 |
| Income (1939) | 146 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Occupation | Helper |
| Township / Ward | Chicago |
| Est. Birth Year | ~1917 |
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 |
|---|---|---|---|---|
| Alice Mcdermott | Daughter | — | 25 | ~1915 |
| Dorothy Mcdermott | Daughter | — | 12 | ~1928 |
| Irene Mcdermott | Daughter | — | 14 | ~1926 |
| Catherine Mcdermott | Daughter | — | 20 | ~1920 |
| Margaret Mcdermott | Daughter | — | 26 | ~1914 |
| Agnes Mcdermott | Daughter | — | 22 | ~1918 |
| John Mcdermott | Head | — | 51 | ~1889 |
| James Mcdermott | Son | — | 10 | ~1930 |
| John Mcdermott | Son | — | 23 | ~1917 |
| Agnes Mcdermott | Spouse | — | 48 | ~1892 |
Census Appearances
1930
Cook, Illinois
Son, age 14
Cook, Illinois · implied b. ~1916 — 10 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McDermott |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 14 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Free State Ireland |
| Mother's Birthplace | Illinois |
| Occupation | none |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Cook-County, Illinois
Son, age 23
Cook-County, Illinois · implied b. ~1917 — 10 household members
| Surname | McDermott |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 23 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Occupation | Helper |
| Industry | Meat Mkt |
| Class of Worker | PW |
| Hours Worked | 3 |
| Income (1939) | 146 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
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 Mcdermott across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
John Mcdermott
Son · 1940 · age 23 · b. ~1917 · Illinois
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Sibling
Agnes Mcdermott
Sibling · 1940 · age 22
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Dorothy Mcdermott
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Catherine Mcdermott
Sibling · 1940 · age 20
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Irene Mcdermott
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Mcdermott
Sibling · 1940 · age 10
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Alice Mcdermott
Sibling · 1940 · age 25
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Margaret Mcdermott
Sibling · 1940 · age 26
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 — Cook-County, Illinois
Open full size
1940 US Federal Census — Cook-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00952-00744)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Ludwig Lomnicki | 40 | Head | Painter | Germany |
| 2 | Emma Lomnicki | 41 | Wife | — | Germany |
| 3 | Hildegarde Lomnicki | 15 | Daughter | — | Germany |
| 4 | Eleanor Lomnicki | 12 | Daughter | — | Illinois |
| 5 | John Kozitaki | 47 | Head | Laborer | Wisconsin |
| 6 | Margaret Kozitaki | 47 | Wife | — | Illinois |
| 7 | Robert Kozitaki | 18 | Son | Laborer | Illinois |
| 8 | John Kozitaki | 16 | Son | — | Illinois |
| 9 | Rosemary Kozitaki | 12 | Daughter | — | Illinois |
| 10 | Leonard Kozitaki | 11 | Son | — | Illinois |
| 11 | Joseph Bruno | 34 | Head | Mail Carrier | Illinois |
| 12 | Jennie Bruno | 30 | Wife | — | Illinois |
| 13 | Joan Bruno | 4 | Daughter | — | Illinois |
| 14 | John Mcdermott | 51 | Head | Police Officer | New York |
| 15 | Agnes Mcdermott | 48 | Wife | — | New York |
| 16 | Margaret Mcdermott | 26 | Daughter | Clerk | Illinois |
| 17 | Alice Mcdermott | 25 | Daughter | Police Officer | Illinois |
| 18 | John Mcdermott THIS PERSON | 23 | Son | Helper | Illinois |
| 19 | Agnes Mcdermott | 22 | Daughter | Clerk | Illinois |
| 20 | Catherine Mcdermott | 20 | Daughter | Clerk | Illinois |
| 21 | Irene Mcdermott | 14 | Daughter | — | Illinois |
| 22 | Dorothy Mcdermott | 12 | Daughter | — | Illinois |
| 23 | James Mcdermott | 10 | Son | — | Illinois |
| 24 | Henry G. Tremblay | 50 | Head | Salesman | Iowa |
| 25 | Teresa Tremblay | 43 | Wife | — | Illinois |
| 26 | Robert Tremblay | 20 | Son | Auto Tech | Illinois |
| 27 | Richard Tremblay | 15 | Son | — | Illinois |
| 28 | Edward Ruzich | 50 | Head | Electrician | Yugoslavia |
| 29 | Stanka Ruzich | 43 | Wife | — | Yugoslavia |
| 30 | Vincent Ruzich | 12 | Stepson | — | Yugoslavia |
| 31 | Mary Boyne | 57 | Head | — | Illinois |
| 32 | Theresa Boyne | 29 | Daughter | — | Illinois |
| 33 | Lawrence Boyne | 24 | Son | Laborer | Illinois |
| 34 | Ludmil Cattle | 33 | Son-in-law | Attendant | Illinois |
| 35 | Geraldine Cattle | 22 | Daughter | — | Illinois |
| 36 | Geraldine Cattle | 2 | Granddaughter | — | Illinois |
| 37 | Louis Manfredi | 39 | Head | Janitor | Italy |
| 38 | Constance Manfredi | 37 | Wife | — | Illinois |
| 39 | Louis Jr. Manfredi | 15 | Son | — | Illinois |
| 40 | Josephine Manfredi | 70 | Mother | — | Italy |
Related Census Records
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)