TM
Thomas Mcmahon — 1940 US Census Record
Model Tree available1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Thomas Mcmahon across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed), with identified parents Joseph & Thomas — first a son (b.~1917), then head of a 6-person household.
Age 23
b. ~1917
Male
Son
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | McMahon |
| Given Name | Thomas |
| 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 | Clerk |
| Industry | Masonite Corp. |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 2100 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same house |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Occupation | Clerk |
| 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.
6 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Thomas | Age | Birth yr |
|---|---|---|---|---|
| Gerald Mcmahon | Son | — | 7 | ~1933 |
| James Mcmahon | Son | — | 11 | ~1929 |
| Myrtle Mcmahon | Head | — | 46 | ~1894 |
| Thomas Mcmahon | Son | — | 23 | ~1917 |
| June Mcmahon | Daughter | — | 14 | ~1926 |
| Marguerite Mcmahon | Daughter | — | 21 | ~1919 |
Census Appearances
1920
Cook, Illinois
Son, age 2
Cook, Illinois · implied b. ~1918 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | Thomas |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 2 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Illinois |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1930
Cook, Illinois
Son, age 13
Cook, Illinois · implied b. ~1917 — 7 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | Thomas |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 13 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Illinois |
| 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 — 6 household members
| Surname | McMahon |
| Given Name | Thomas |
| 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 | Clerk |
| Industry | Masonite Corp. |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 2100 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same house |
| 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 Thomas Mcmahon across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father Joseph Mcmahon (~0.92 confidence) and father Thomas Mcmahon (~0.92 confidence) and mother Mary Mcmahon (~0.92 confidence) and mother Myrtle Mcmahon (~0.92 confidence). The pedigree spans 1 generation with 4 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
Joseph Mcmahon
b. ~1885
Source father
● Household
· direct · ~0.92
Father
Thomas Mcmahon
b. ~1890
Source father
● Household
· direct · ~0.92
Mother
Mary Mcmahon
b. ~1889
Source mother
● Household
· direct · ~0.92
Mother
Myrtle Mcmahon
b. ~1894
Source mother
● Household
· direct · ~0.92
This person
Anchor record
Thomas Mcmahon
Son · 1940 · age 23 · b. ~1917 · Illinois
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Sibling
Gerald Mcmahon
Sibling · 1940 · age 7
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Marguerite Mcmahon
Sibling · 1940 · age 21
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
June Mcmahon
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Mcmahon
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 — 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-t0627-00958-00805)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Martha Ferretti | 42 | Wife | — | Indiana |
| 42 | Dorothy Ferretti | 8 | Daughter | — | Illinois |
| 43 | Morris Rothenberg | 47 | Head | Manager | Germany |
| 44 | Louise Rothenberg | 40 | Wife | — | Germany |
| 45 | Eleanor Rothenberg | 19 | Daughter | Clerk | Illinois |
| 46 | Solomon Rothenberg | 66 | Father | — | Poland |
| 47 | Nettie Rothenberg | 68 | Mother | — | Poland |
| 48 | Anna Vitoris | 48 | Head | — | Michigan |
| 49 | John Vitoris | 18 | Son | — | Illinois |
| 50 | Carole Vitoris | 13 | Daughter | — | Illinois |
| 51 | George Vitoris | 8 | Son | — | Illinois |
| 52 | Ethel Denite | 23 | Niece | Switchboard Operator | Illinois |
| 53 | Thomas Corcoran | 41 | Head | Draftsman | New York |
| 54 | Julia D. Corcoran | 38 | Wife | — | Illinois |
| 55 | Anne Mary Corcoran | 16 | Daughter | — | Illinois |
| 56 | Thomas Corcoran | 14 | Son | — | Illinois |
| 57 | Kenneth Rice | 35 | Head | Clerk | Montana |
| 58 | Alice Rice | 35 | Wife | Stenographer | Illinois |
| 59 | Nellie Reynolds | 61 | Mother-in-law | — | Eire |
| 60 | Edward Regally | 30 | Head | Postal Clerk | Illinois |
| 61 | Eileen Regally | 31 | Wife | Teacher | Illinois |
| 62 | Thomas Regally | 1 | Son | — | Illinois |
| 63 | Myrtle Mcmahon | 46 | Head | — | Illinois |
| 64 | Thomas Mcmahon THIS PERSON | 23 | Son | Clerk | Illinois |
| 65 | Marguerite Mcmahon | 21 | Daughter | Stenographer | Illinois |
| 66 | June Marie Mcmahon | 14 | Daughter | — | Illinois |
| 67 | James Mcmahon | 11 | Son | — | Illinois |
| 68 | Gerald Mcmahon | 7 | Son | — | Illinois |
| 69 | Eldworth Bentley | 38 | Head | Electrical Engineer | Illinois |
| 70 | Mary Bentley | 37 | Wife | — | Illinois |
| 71 | Robert Bentley | 10 | Son | — | Illinois |
| 72 | Alan Bentley | 3 | Son | — | Illinois |
| 73 | Line Charles Bentley | 68 | Father-in-law | — | Michigan |
| 74 | William Lake | 52 | Head | Chief Clerk | Illinois |
| 75 | Cecil Lake | 49 | Wife | — | Illinois |
| 76 | Alice Mae Lake | 19 | Daughter | — | Illinois |
| 77 | Cecil Lake | 14 | Daughter | — | Illinois |
| 78 | Margie Lake | 11 | Daughter | — | Illinois |
| 79 | Arthur Clifford | 42 | Head | Cashier | Illinois |
| 80 | Mary Clifford | 40 | Wife | — | Illinois |
Pedigree Summary
Thomas + 4 siblings
Gen 1 · 4 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)