JM
John Monahan — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Suffolk-County, Massachusetts
Our Model Tree links this John Monahan across the 1930 and 1940 US Censuses in Suffolk-County, Massachusetts (XGBoost, ~Confirmed) — first a son (b.~1912), then head of a 9-person household.
Age 28
b. ~1912
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Suffolk-County, Massachusetts |
| Surname | Monahan |
| Given Name | John B. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 28 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| Additional Details | |
| Occupation | Clerk |
| Industry | Cold Storage |
| Class of Worker | PW |
| Hours Worked | 48 |
| Income (1939) | 1400 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Clerk |
| Township / Ward | Boston City |
| Est. Birth Year | ~1912 |
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.
9 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Francis Monahan | Son | — | 25 | ~1915 |
| John Monahan | Son | — | 28 | ~1912 |
| James Hazelton | Head | — | 50 | ~1890 |
| Ellen Monahan | Spouse | — | 63 | ~1877 |
| Dennis Monahan | Other | — | 66 | ~1874 |
| James Hazelton | Son | — | 18 | ~1922 |
| Helen Monahan | Daughter | — | 21 | ~1919 |
| Phyllis Hazelton | Daughter | — | 17 | ~1923 |
| Mary Hazelton | Spouse | — | 47 | ~1893 |
Census Appearances
1930
Suffolk, Massachusetts
Son, age 17
Suffolk, Massachusetts · implied b. ~1913 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Monahan |
| Given Name | John B |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 17 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Occupation | Shipper |
| Industry | Fish Market |
| Class of Worker | W |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Suffolk-County, Massachusetts
Son, age 28
Suffolk-County, Massachusetts · implied b. ~1912 — 9 household members
| Surname | Monahan |
| Given Name | John B. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 28 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| Occupation | Clerk |
| Industry | Cold Storage |
| Class of Worker | PW |
| Hours Worked | 48 |
| Income (1939) | 1400 |
| 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 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
John Monahan
Son · 1940 · age 28 · b. ~1912 · Massachusetts
★ You are viewing this record
Sibling
Francis Monahan
Sibling · 1940 · age 25
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Hazelton
Sibling · 1940 · age 18
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Phyllis Hazelton
Sibling · 1940 · age 17
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Helen Monahan
Sibling · 1940 · age 21
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 — Suffolk-County, Massachusetts
Open full size
1940 US Federal Census — Suffolk-County, Massachusetts
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01657-00013)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Daniel J. Donoghue | 52 | Head | Motorman | Massachusetts |
| 42 | Mary A. Donoghue | 52 | Wife | — | Massachusetts |
| 43 | Mary S. Donoghue | 20 | Daughter | Clerk | Massachusetts |
| 44 | Bernadette Donoghue | 16 | Daughter | — | Massachusetts |
| 45 | John Donoghue | 14 | Son | — | Massachusetts |
| 46 | Edward W. Jackson | 33 | Head | Salesman | Massachusetts |
| 47 | Mary L. Jackson | 32 | Wife | — | Massachusetts |
| 48 | Francis Barlett | 66 | Head | Blacksmith | Newfoundland |
| 49 | Mary K. Barlett | 59 | Wife | — | Newfoundland |
| 50 | Ethel M. Savagane | 33 | Head | Operator | Massachusetts |
| 51 | Helen F. Savagane | 30 | Sister | File Clerk | Massachusetts |
| 52 | Katherine E. Savagane | 23 | Sister | Operator | Massachusetts |
| 53 | Alice Colbert | 56 | Head | — | Newfoundland |
| 54 | John J. Colbert | 27 | Son | Attendant | Massachusetts |
| 55 | Ellen Colbert | 28 | Daughter | Card Filer | Newfoundland |
| 56 | Alice Colbert | 22 | Niece | Commercial Artist | Massachusetts |
| 57 | Michael H. Duffy | 40 | Head | Clerk | Massachusetts |
| 58 | Mary M. Duffy | 36 | Wife | — | Massachusetts |
| 59 | Joseph L. Arthur | 45 | Head | Package Store | Massachusetts |
| 60 | Veronica C. Arthur | 45 | Wife | — | Massachusetts |
| 61 | Catalin Arthur | 15 | Daughter | — | Massachusetts |
| 62 | Lawrence Arthur | 39 | Brother | Clerk | Massachusetts |
| 63 | Thomas Arthur | 41 | Brother | Time Keeper | Massachusetts |
| 64 | James E. Hazelton | 50 | Head | Engineer | Massachusetts |
| 65 | Mary M. Hazelton | 47 | Wife | — | Massachusetts |
| 66 | James E. Jr. Hazelton | 18 | Son | Errand Boy | Massachusetts |
| 67 | Phyllis M. Hazelton | 17 | Daughter | — | Massachusetts |
| 68 | Dennis J. Monahan | 66 | Father | Inspector | Massachusetts |
| 69 | Ellen Monahan | 63 | Wife | — | Massachusetts |
| 70 | John B. Monahan THIS PERSON | 28 | Son | Clerk | Massachusetts |
| 71 | Francis L. Monahan | 25 | Son | Helper | Massachusetts |
| 72 | Helen R. Monahan | 21 | Daughter | Clerk | Massachusetts |
| 73 | Robert A. Ferneled | 58 | Head | Dispatcher | Massachusetts |
| 74 | Agnes Ferneled | 58 | Wife | — | Massachusetts |
| 75 | Marion Ferneled | 25 | Daughter | Stenographer | New York |
| 76 | Daniel J. Gibbons | 47 | Head | Custodian | Massachusetts |
| 77 | Elizabeth F. Gibbons | 46 | Wife | — | Massachusetts |
| 78 | Margaret H. Gibbons | 18 | Daughter | — | Maine |
| 79 | Doris J. Gibbons | 11 | Daughter | — | Massachusetts |
| 80 | John Morrelli | 45 | Head | Bar Keeper | Italy |
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)