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John Mcmahon — 1930 US Census Record
Model Tree available1930 United States Federal Census · Middlesex, Massachusetts
Our Model Tree links this John Mcmahon across the 1910, 1920, 1930 and 1940 US Censuses in Middlesex, Massachusetts (XGBoost, ~Confirmed), with identified parents Thomas & Thomas — first a son (b.~1904), then head of a 5-person household.
Age 26
b. ~1904
Male
Son
Born: Massachusetts
Single
1930 Census Record Details
| Census Year | 1930 |
| Location | Middlesex, Massachusetts |
| Surname | McMahon |
| Given Name | John F. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 26 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Vermont |
| Mother's Birthplace | Massachusetts |
| Additional Details | |
| Occupation | Clerk |
| Industry | Drug Store |
| Class of Worker | W |
| Can Read/Write | Yes |
| Veteran | No |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Clerk |
| Township / Ward | Somerville City |
| Est. Birth Year | ~1904 |
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 1930 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Annie Mcmahon | Daughter | — | 18 | ~1912 |
| Mary Mcmahon | Daughter | — | 24 | ~1906 |
| Thomas Mcmahon | Head | — | 64 | ~1866 |
| Margaret Mcmahon | Other | — | 58 | ~1872 |
| John Mcmahon | Son | — | 26 | ~1904 |
Census Appearances
1910
Middlesex, Massachusetts
Son, age 5
Middlesex, Massachusetts · implied b. ~1905 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 5 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Vermont |
| Mother's Birthplace | Massachusetts |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1920
Middlesex, Massachusetts
Son, age 16
Middlesex, Massachusetts · implied b. ~1904 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 16 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Vermont |
| Mother's Birthplace | Massachusetts |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1930
Middlesex, Massachusetts
Son, age 26
Middlesex, Massachusetts · implied b. ~1904 — 5 household members
| Surname | McMahon |
| Given Name | John F. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 26 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Vermont |
| Mother's Birthplace | Massachusetts |
| Occupation | Clerk |
| Industry | Drug Store |
| Class of Worker | W |
| Can Read/Write | Yes |
| Veteran | No |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Middlesex-County, Massachusetts
Head, age 36
Middlesex-County, Massachusetts · implied b. ~1904
●
Primary link
· ~Confirmed · 1 source
XGBoost
| Surname | McMahan |
| Given Name | John F |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 36 |
| Marital Status | Married |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Somerville City |
| 1935 Residence (County) | Middlesex |
| Occupation | school teacher |
| Industry | public junior high |
| Class of Worker | GW |
| Hours Worked | 31 |
| Income (1939) | 2000 |
| Highest Grade | C 5 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
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 4 US Census years (1910, 1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father Thomas Mcmahon (~0.92 confidence) and father Thomas Mcmahon (~0.92 confidence) and father Thomas Mcmahon (~0.92 confidence) and mother Margaret Mcmahon (~0.92 confidence) and mother Margaret Mcmahon (~0.92 confidence). The pedigree spans 1 generation with 5 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
Thomas Mcmahon
b. ~1863
Source father
● Household
· direct · ~0.92
Father
Thomas Mcmahon
b. ~1866
Source father
● Household
· direct · ~0.92
Father
Thomas Mcmahon
b. ~1869
Source father
● Household
· direct · ~0.92
Mother
Margaret Mcmahon
b. ~1873
Source mother
● Household
· direct · ~0.92
Mother
Margaret Mcmahon
b. ~1875
Source mother
● Household
· direct · ~0.92
This person
Anchor record
John Mcmahon
Son · 1930 · age 26 · b. ~1904 · Massachusetts
★ You are viewing this record
Sibling
Mary Mcmahon
Sibling · 1930 · age 24
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Annie Mcmahon
Sibling · 1930 · age 18
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
1930 US Federal Census — Middlesex, Massachusetts
Open full size
1930 US Federal Census — Middlesex, Massachusetts
Page Contents
50 people indexed on this census page (ia:1930:massachusettscensus00reel927:0695)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Eugene A. Geroux | 27 | Head | Lawyer | Massachusetts |
| 2 | Maud E. Geroux | 27 | Wife-H | — | Massachusetts |
| 3 | Eugene H. Jr. Geroux | 1 | Son | — | Massachusetts |
| 4 | John H. Geroux | 0 | Son | — | Massachusetts |
| 5 | Elizabeth C. Cotter | 20 | Sister-in-law | — | Massachusetts |
| 6 | Walter J. Moran | 31 | Head | Salesman | Massachusetts |
| 7 | Margaret G. Moran | 29 | Wife-H | — | Massachusetts |
| 8 | Walter J. Moran | 2 | Son | — | Massachusetts |
| 9 | Michael Geary | 49 | Boarder | — | Irish Free State |
| 10 | Francis J. Daly | 34 | Head | Watchman | Irish Free State |
| 11 | Julia Daly | 33 | Wife-H | Laundress | Irish Free State |
| 12 | Francis D. Daly | 5 | Son | — | Massachusetts |
| 13 | Joan M. Daly | 3 | Daughter | — | Massachusetts |
| 14 | John Langone | 26 | Head | Soldier | Massachusetts |
| 15 | Eleanor Langone | 26 | Wife-H | — | Massachusetts |
| 16 | John Langone | 1 | Son | — | Massachusetts |
| 17 | Roger M. Welch | 42 | Head | Conductor | Maine |
| 18 | Margaret L. Welch | 42 | Wife-H | — | Irish Free State |
| 19 | Roy Milbury | 51 | Head | Handyman | Canada English |
| 20 | Selena Milbury | 50 | Wife-H | — | Canada English |
| 21 | Harlan Milbury | 22 | Son | Sales Clerk | Massachusetts |
| 22 | John Milbury | 20 | Son | Driver | Massachusetts |
| 23 | Adeline Milbury | 19 | Daughter | Claim Agent | Massachusetts |
| 24 | Kathryn Milbury | 16 | Daughter | — | Massachusetts |
| 25 | Vincent Milbury | 10 | Son | — | Massachusetts |
| 26 | Roy Jr. Milbury | 7 | Son | — | Massachusetts |
| 27 | Birkirk C. Mackay | 53 | Head | Superintendent | Sweden |
| 28 | Lola M. Mackay | 36 | Wife-H | — | Massachusetts |
| 29 | Harvey O. Young | 42 | Head | Superintendent | Canada English |
| 30 | Katherine M. Young | 40 | Wife-N | — | Canada English |
| 31 | Dorothy G. Young | 20 | Daughter | Stenographer | Massachusetts |
| 32 | Cecil G. Young | 21 | Son | — | Massachusetts |
| 33 | George S. Hutchinson | 64 | Head | Fireman | New Hampshire |
| 34 | Alice G. Hutchinson | 46 | Wife-H | Stitcher | Massachusetts |
| 35 | Mildred Hutchinson | 23 | Daughter | Stenographer | Massachusetts |
| 36 | Mary M. Thompson | 49 | Head-H | — | Massachusetts |
| 37 | William L. Thompson | 23 | Son | Shipper | Massachusetts |
| 38 | Edna M. Thompson | 21 | Daughter | Stenographer | Massachusetts |
| 39 | Wesley J. Thompson | 19 | Son | — | Massachusetts |
| 40 | William A. Stevens | 58 | Brother | Inspector | Massachusetts |
| 41 | Thomas J. Mcmahon | 64 | Head | Foreman | Vermont |
| 42 | Margaret J. Mcmahon | 58 | Wife-H | — | Massachusetts |
| 43 | John F. Mcmahon THIS PERSON | 26 | Son | Clerk | Massachusetts |
| 44 | Mary F. Mcmahon | 24 | Daughter | Clerk | Massachusetts |
| 45 | Annie R. Mcmahon | 18 | Daughter | Clerk | Massachusetts |
| 46 | Margaret A. Daniels | 45 | Head | Cook | Irish Free State |
| 47 | William S. Daniels | 22 | Son | Mechanic | Massachusetts |
| 48 | Irene L. Daniels | 20 | Daughter-in-law | — | Canada English |
| 49 | Margaret Daniels | 1 | Granddaughter | — | Massachusetts |
| 50 | Mary R. Daniels | 20 | Daughter | — | Massachusetts |
Pedigree Summary
John + 2 siblings
Gen 1 · 5 parents
~0.92
Max depth 4 (1900–1950 window)
About This Record & Model Tree
This record was independently indexed by YourRoots from the 1930 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)