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John Monahan — 1940 US Census Record
Model Tree available1940 United States Federal Census · Middlesex-County, Massachusetts
Our Model Tree links this John Monahan across the 1920, 1930 and 1940 US Censuses in Middlesex-County, Massachusetts (XGBoost, ~Confirmed), with identified parents Elizabeth & John — first a son (b.~1909), then head of a 6-person household.
Age 31
b. ~1909
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Middlesex-County, Massachusetts |
| Surname | Monahan |
| Given Name | John |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 31 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Somerville City |
| 1935 Residence (County) | MIDDLESEX |
| Additional Details | |
| Occupation | Shipping Clerk |
| Industry | Metal Products |
| Class of Worker | PW |
| Hours Worked | 43 |
| Income (1939) | 1250 |
| Highest Grade | H-4 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Shipping Clerk |
| Township / Ward | Somerville City |
| Est. Birth Year | ~1909 |
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 John | Age | Birth yr |
|---|---|---|---|---|
| Anthony Courtland | Other | — | 9 | ~1931 |
| Clare Monahan | Daughter | — | 18 | ~1922 |
| Mary Courtland | Daughter | — | 34 | ~1906 |
| Agnes Monahan | Daughter | — | 29 | ~1911 |
| John Monahan | Son | — | 31 | ~1909 |
| Annie Monahan | Head | — | 61 | ~1879 |
Census Appearances
1920
Middlesex, Massachusetts
Son, age 11
Middlesex, Massachusetts · implied b. ~1909 — 9 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Monahan |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 11 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| 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 21
Middlesex, Massachusetts · implied b. ~1909 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Monahan |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 21 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Occupation | Clerk |
| Industry | Post Office |
| Class of Worker | W |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Middlesex-County, Massachusetts
Son, age 31
Middlesex-County, Massachusetts · implied b. ~1909 — 6 household members
| Surname | Monahan |
| Given Name | John |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 31 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Somerville City |
| 1935 Residence (County) | MIDDLESEX |
| Occupation | Shipping Clerk |
| Industry | Metal Products |
| Class of Worker | PW |
| Hours Worked | 43 |
| Income (1939) | 1250 |
| Highest Grade | H-4 |
| 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 Monahan across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: mother Elizabeth Monahan (~0.92 confidence) and father John Monahan (~0.92 confidence) and mother Mary Monahan (~0.92 confidence) and mother Annie Monahan (~0.92 confidence). The pedigree spans 1 generation with 4 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Mother
Elizabeth Monahan
b. ~1875
Source mother
● Household
· direct · ~0.92
Father
John Monahan
b. ~1875
Source father
● Household
· direct · ~0.92
Mother
Mary Monahan
b. ~1878
Source mother
● Household
· direct · ~0.92
Mother
Annie Monahan
b. ~1879
Source mother
● Household
· direct · ~0.92
This person
Anchor record
John Monahan
Son · 1940 · age 31 · b. ~1909 · Massachusetts
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Sibling
Agnes Monahan
Sibling · 1940 · age 29
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Mary Courtland
Sibling · 1940 · age 34
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Clare Monahan
Sibling · 1940 · 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
1940 US Federal Census — Middlesex-County, Massachusetts
Open full size
1940 US Federal Census — Middlesex-County, Massachusetts
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01705-00563)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Joseph O'Connell | 18 | son | Baker'S Assistant | Massachusetts |
| 2 | Eleanor O'Connell | 13 | daughter | — | Massachusetts |
| 3 | Francis O'Connell | 27 | son | Chauffeur | Massachusetts |
| 4 | Marguerite O'Connell | 27 | daughter-in-law | — | Massachusetts |
| 5 | John Kinsella | 49 | head | Steam Fitter | Massachusetts |
| 6 | Frances Kinsella | 48 | wife | — | Massachusetts |
| 7 | Helen Kinsella | 20 | daughter | — | Massachusetts |
| 8 | Frances Kinsella | 18 | daughter | — | Massachusetts |
| 9 | John Kinsella | 16 | son | — | Massachusetts |
| 10 | Herman Lee | 45 | head | Clerk | South Carolina |
| 11 | Rosa Lee | 46 | wife | — | Pennsylvania |
| 12 | Louis Casco | 39 | head | Mechanic | Italy |
| 13 | Catherine Casco | 41 | wife | — | Massachusetts |
| 14 | Louis Casco | 16 | son | — | Massachusetts |
| 15 | Joseph Casco | 15 | son | — | Massachusetts |
| 16 | Catherine Casco | 13 | daughter | — | Massachusetts |
| 17 | Paul Casco | 8 | son | — | Massachusetts |
| 18 | Sylvia Casco | 6 | daughter | — | Massachusetts |
| 19 | Leo Jennings | 26 | head | Engineer'S Atten | Massachusetts |
| 20 | Doris Jennings | 25 | wife | Operator Machine | Massachusetts |
| 21 | William Dooling | 38 | head | Statistician | Massachusetts |
| 22 | Mary Dooling | 34 | wife | — | Massachusetts |
| 23 | Thomas Dooling | 12 | son | — | Massachusetts |
| 24 | Mary Dooling | 10 | daughter | — | Massachusetts |
| 25 | Charles Babcock | 34 | head | Machinist | Massachusetts |
| 26 | Agnes Babcock | 30 | wife | Typist | Massachusetts |
| 27 | Annie Monahan | 61 | head | — | Rhode Island |
| 28 | John Monahan THIS PERSON | 31 | son | Shipping Clerk | Massachusetts |
| 29 | Agnes Monahan | 29 | daughter | Stenographer | Massachusetts |
| 30 | Mary Courtland | 34 | daughter | Tabulating Clerk | Massachusetts |
| 31 | Anthony Courtland | 9 | grandson | — | Pennsylvania |
| 32 | Clare Monahan | 18 | daughter | — | Massachusetts |
| 33 | Bridget Davis | 77 | head | — | Eire |
| 34 | Frank Davis | 48 | son | — | Massachusetts |
| 35 | Helen Davis | 50 | daughter | — | Massachusetts |
| 36 | Thomas Davis | 44 | son | Salesman | Massachusetts |
| 37 | Robert Tondell | 22 | grandson | Clerk | Massachusetts |
| 38 | William Boyce | 36 | head | Salesman | Massachusetts |
| 39 | Margaret Boyce | 34 | wife | — | Massachusetts |
| 40 | Helen Boyce | 6 | daughter | — | Massachusetts |
Pedigree Summary
John + 3 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)