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John Mcmahon — 1940 US Census Record
Model Tree available1940 United States Federal Census · St.-Louis-City-County, Missouri
Our Model Tree links this John Mcmahon across the 1920, 1930 and 1940 US Censuses in St.-Louis-City-County, Missouri (XGBoost, ~Confirmed), with identified parents John & Clara — first a son (b.~1919), then head of a 5-person household.
Age 21
b. ~1919
Male
Son
Born: Missouri
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | St.-Louis-City-County, Missouri |
| Surname | McMahon |
| Given Name | John Jr. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 21 |
| Marital Status | Single |
| Birthplace | Missouri |
| 1935 Residence (City) | St. Louis City |
| 1935 Residence (County) | St. Louis City |
| Additional Details | |
| Occupation | tinner & mechanic |
| Industry | Refrigeration mfg. |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 1050 |
| Highest Grade | Hs 1 |
| 1935 Residence | Same house |
| Birth State | Missouri |
| Birth Country | United States |
| Birthplace (normalized) | missouri |
| Occupation | Tinner & Mechanic |
| Township / Ward | St Louis City |
| Est. Birth Year | ~1919 |
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.
5 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Cleora Mcmahon | Daughter | — | 23 | ~1917 |
| John Mcmahon | Head | — | 54 | ~1886 |
| Mary Mcmahon | Other | — | 74 | ~1866 |
| John Mcmahon | Son | — | 21 | ~1919 |
| Alma Mcmahon | Spouse | — | 49 | ~1891 |
Census Appearances
1920
St Louis, …
Son, age 1
St Louis, Missouri · implied b. ~1919 — 4 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 1 |
| Marital Status | Single |
| Birthplace | Missouri |
| Father's Birthplace | Missouri |
| Mother's Birthplace | Missouri |
| Can Read | No |
| Can Write | No |
| Speaks English | No |
| Birth State | Missouri |
| Birth Country | United States |
| Birthplace (normalized) | missouri |
1930
St Louis, …
Son, age 11
St Louis, Missouri · implied b. ~1919 — 4 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | John Jr |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 11 |
| Marital Status | Single |
| Birthplace | Missouri |
| Father's Birthplace | Missouri |
| Mother's Birthplace | Missouri |
| Can Read/Write | Yes |
| Birth State | Missouri |
| Birth Country | United States |
| Birthplace (normalized) | missouri |
1940
St.-Louis-City-County, Missouri
Son, age 21
St.-Louis-City-County, Missouri · implied b. ~1919 — 5 household members
| Surname | McMahon |
| Given Name | John Jr. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 21 |
| Marital Status | Single |
| Birthplace | Missouri |
| 1935 Residence (City) | St. Louis City |
| 1935 Residence (County) | St. Louis City |
| Occupation | tinner & mechanic |
| Industry | Refrigeration mfg. |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 1050 |
| Highest Grade | Hs 1 |
| 1935 Residence | Same house |
| Birth State | Missouri |
| Birth Country | United States |
| Birthplace (normalized) | missouri |
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 Mcmahon across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father John Mcmahon (~0.92 confidence) and mother Clara Mcmahon (~0.92 confidence) and mother Alma Mcmahon (~0.92 confidence). The pedigree spans 1 generation with 3 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
John Mcmahon
b. ~1886
Source father
● Household
· direct · ~0.92
Mother
Clara Mcmahon
b. ~1888
Source mother
● Household
· direct · ~0.92
Mother
Alma Mcmahon
b. ~1891
Source mother
● Household
· direct · ~0.92
This person
Anchor record
John Mcmahon
Son · 1940 · age 21 · b. ~1919 · Missouri
★ You are viewing this record
Sibling
Cleora Mcmahon
Sibling · 1940 · age 23
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 — St.-Louis-City-County, Missouri
Open full size
1940 US Federal Census — St.-Louis-City-County, Missouri
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-02211-00665)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Gertrude Roberts | 60 | Head | — | Missouri |
| 2 | Harold Roberts | 36 | Son | Fireman | Missouri |
| 3 | Marion Roberts | 36 | Daughter | Stenographer | Missouri |
| 4 | Harry Schneidr | 43 | Head | Insurance Agent | Russia |
| 5 | Celia Schneidr | 36 | Wife | — | Russia |
| 6 | Senne Schneidr | 14 | Daughter | — | Missouri |
| 7 | Louis Suddarth | 30 | Head | Painting Bus. Operator | United States |
| 8 | Jewell Suddarth | 32 | Wife | Stenographer | Missouri |
| 9 | Joy Prior | 11 | Step daughter | — | Missouri |
| 10 | Ella Mcintosh | 50 | Mother-in-law | — | Missouri |
| 11 | Albert De Workin | 27 | Head | Vegetables & Fruit Salesman | Missouri |
| 12 | Sylvia De Workin | 26 | Wife | — | Russia |
| 13 | Barbara De Workin | 3 | Daughter | — | Missouri |
| 14 | Sheila De Workin | 1 | Daughter | — | Missouri |
| 15 | John Mcmahon | 54 | Head | House Painter | Missouri |
| 16 | Alma Mcmahon | 49 | Wife | — | Missouri |
| 17 | Cleora Mcmahon | 23 | Daughter | — | Missouri |
| 18 | John Jr. Mcmahon THIS PERSON | 21 | Son | Tinner & Mechanic | Missouri |
| 19 | Mary Mcmahon | 74 | Mother | — | Missouri |
| 20 | Bert O. Shea | 55 | Head | Accounting Clerk | United States |
| 21 | Carrie Shea | 56 | Wife | — | Missouri |
| 22 | Robert C. Shea | 21 | Son | Laborer | Missouri |
| 23 | Morris Wyloge | 23 | Head | Shoe Salesman | Missouri |
| 24 | Adele Wyloge | 22 | Wife | Cashier | Missouri |
| 25 | Betty D. Wyloge | 1 | Daughter | — | California |
| 26 | Sarah Spector | 43 | Mother-in-law | — | Russia |
| 27 | Jeanette Spector | 21 | Sister-in-law | Presser & Draper | Oklahoma |
| 28 | Milton Saldofsky | 29 | Head | Order Filler & Salesman | Missouri |
| 29 | Ida Saldofsky | 27 | Wife | — | Missouri |
| 30 | Sally Saldofsky | 4 | Daughter | — | Missouri |
| 31 | Rita Saldofsky | 0 | Daughter | — | Missouri |
| 32 | Joseph Clark | 51 | Head | Director | Kentucky |
| 33 | Maude Montague | 48 | Housekeeper | Housekeeper | Missouri |
| 34 | George Montague | 25 | Housekeeper's son | Painter | Missouri |
| 35 | Milton Schliesser | 36 | Head | Draftsman | Illinois |
| 36 | Rose Schliesser | 40 | Wife | — | Illinois |
| 37 | Robert Schliesser | 4 | Son | — | Missouri |
| 38 | Albert M. Bonzo | 65 | Head | — | Ohio |
| 39 | Lucida Bonzo | 49 | Wife | — | Missouri |
| 40 | Albert S. Bonzo | 17 | Son | Delivery Boy | Missouri |
Related Census Records
Pedigree Summary
John + 1 sibling
Gen 1 · 3 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)