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John Mahoney — 1940 US Census Record
Model Tree available1940 United States Federal Census · Madison-County, Illinois
Our Model Tree links this John Mahoney across the 1920, 1930 and 1940 US Censuses in Madison-County, Illinois (XGBoost, ~Confirmed), with identified parents Valerius & Al — first a son (b.~1911), then head of a 4-person household.
Age 29
b. ~1911
Male
Son
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Madison-County, Illinois |
| Surname | Mahoney |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 29 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Alton City |
| 1935 Residence (County) | Madison |
| Additional Details | |
| Occupation | Salesman |
| Industry | Shipley Hardware |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 298 |
| Highest Grade | H 4 |
| 1935 Residence | Same House |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Occupation | Salesman |
| Township / Ward | Alton City |
| Est. Birth Year | ~1911 |
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 |
|---|---|---|---|---|
| Al Mahoney | Head | — | 51 | ~1889 |
| John Mahoney | Son | — | 29 | ~1911 |
| Arthur Mahoney | Son | — | 25 | ~1915 |
| Helen Mahoney | Spouse | — | 44 | ~1896 |
Census Appearances
1920
Madison, Illinois
Son, age 8
Madison, Illinois · implied b. ~1912 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Mahoney |
| Given Name | John H. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 8 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Wisconsin |
| Mother's Birthplace | Illinois |
| Can Read | Yes |
| Speaks English | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1930
Madison, Illinois
Son, age 19
Madison, Illinois · implied b. ~1911 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Mahoney |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 19 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Wisconsin |
| Mother's Birthplace | Illinois |
| Occupation | none |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Madison-County, Illinois
Son, age 29
Madison-County, Illinois · implied b. ~1911 — 4 household members
| Surname | Mahoney |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 29 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Alton City |
| 1935 Residence (County) | Madison |
| Occupation | Salesman |
| Industry | Shipley Hardware |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 298 |
| Highest Grade | H 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 John Mahoney across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father Valerius Mahoney (~0.92 confidence) and father Al Mahoney (~0.92 confidence) and mother Helen Mahoney (~0.92 confidence) and mother Helen Mahoney (~0.92 confidence). The pedigree spans 1 generation with 4 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
Valerius Mahoney
b. ~1888
Source father
● Household
· direct · ~0.92
Father
Al Mahoney
b. ~1889
Source father
● Household
· direct · ~0.92
Mother
Helen Mahoney
b. ~1890
Source mother
● Household
· direct · ~0.92
Mother
Helen Mahoney
b. ~1896
Source mother
● Household
· direct · ~0.92
This person
Anchor record
John Mahoney
Son · 1940 · age 29 · b. ~1911 · Illinois
★ You are viewing this record
Sibling
Arthur Mahoney
Sibling · 1940 · age 25
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 — Madison-County, Illinois
Open full size
1940 US Federal Census — Madison-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00848-00755)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Olin C. Unterbrink | 48 | Head | Carpenter | Illinois |
| 2 | Mary E. Unterbrink | 47 | Wife | — | Illinois |
| 3 | Gertrude Unterbrink | 17 | Daughter | — | Illinois |
| 4 | Fred Maul | 54 | Brother-in-law | Laborer | Illinois |
| 5 | August O. Weil | 69 | Head | Engineer | Missouri |
| 6 | Henrietta Weil | 67 | Wife | — | Missouri |
| 7 | John W. Manns | 69 | Head | Packer | Illinois |
| 8 | Cecilia Manns | 62 | Wife | — | Illinois |
| 9 | Olivia Manns | 29 | Daughter | Dressmaker | Illinois |
| 10 | Adam Morick | 89 | Father-in-law | — | Germany |
| 11 | Orville M. Link | 31 | Head | Engineer | Missouri |
| 12 | Bernadine Link | 29 | Wife | Engineer | Illinois |
| 13 | Mary E. Link | 1 | Daughter | — | Illinois |
| 14 | Victor H. Unterbrink | 41 | Head | Draftsman | Illinois |
| 15 | Julia G. Unterbrink | 40 | Wife | — | Illinois |
| 16 | Victor L. Unterbrink | 16 | Son | — | Illinois |
| 17 | Joseph F. Ush | 51 | Head | Brick Layer | Illinois |
| 18 | Appla O. Ush | 44 | Wife | — | Missouri |
| 19 | Betty Ush | 16 | Daughter | — | Illinois |
| 20 | Arthur E. Kirk | 62 | Head | Automotive | Indiana |
| 21 | Lucille Zimmerman | 29 | Daughter | — | Illinois |
| 22 | Fred M. Zimmerman | 3 | Grandson | — | Illinois |
| 23 | Al Mahoney | 51 | Head | Office Work | Wisconsin |
| 24 | Helen O. Mahoney | 44 | Wife | — | Illinois |
| 25 | John Mahoney THIS PERSON | 29 | Son | Salesman | Illinois |
| 26 | Arthur Mahoney | 25 | Son | — | Illinois |
| 27 | John W. Mcadams | 64 | Head | Business Mgr. | Illinois |
| 28 | Hilda Mcadams | 61 | Wife | — | Illinois |
| 29 | John W. Jr. Mcadams | 30 | Son | Advertising Mgr. | Illinois |
| 30 | Alice Mcadams | 27 | Daughter | Stenographer | Illinois |
| 31 | Elizabeth Mcadams | 22 | Daughter | — | Illinois |
| 32 | Eugene H. Halwell | None | Head | — | Arkansas |
| 33 | Halwell | None | Wife | — | Arkansas |
| 34 | Elinor Watson | None | Sister | — | — |
| 35 | Mary Watson | None | Niece | — | — |
| 36 | Alphonse Zahnericht | 54 | Head | Chief Chemist | Missouri |
| 37 | Ida Zahnericht | 47 | Wife | — | Illinois |
| 38 | John Zahnericht | 18 | Son | — | Illinois |
| 39 | James Zahnericht | 16 | Son | — | Illinois |
| 40 | Mary Ann Zahnericht | 8 | Daughter | — | Illinois |
Pedigree Summary
John + 1 sibling
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)