JL
John Leonard — 1940 US Census Record
Model Tree available1940 United States Federal Census · Suffolk-County, Massachusetts
Our Model Tree links this John Leonard across the 1920, 1930 and 1940 US Censuses in Suffolk-County, Massachusetts (XGBoost, ~Confirmed), with identified parents Melvin & Mabel — first a son (b.~1918), then head of a 6-person household.
Age 22
b. ~1918
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Suffolk-County, Massachusetts |
| Surname | Leonard |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 22 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| Additional Details | |
| Occupation | Helper |
| Industry | Printing Co. |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 296 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Occupation | Helper |
| Township / Ward | Boston City |
| Est. Birth Year | ~1918 |
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 |
|---|---|---|---|---|
| Katherine Leonard | Daughter | — | 16 | ~1924 |
| Mary Leonard | Daughter | — | 26 | ~1914 |
| Catherine Leonard | Head | — | 56 | ~1884 |
| Edward Leonard | Son | — | 18 | ~1922 |
| John Leonard | Son | — | 22 | ~1918 |
| James Leonard | Son | — | 28 | ~1912 |
Census Appearances
1920
Suffolk, Massachusetts
Son, age 1
Suffolk, Massachusetts · implied b. ~1919 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leonard |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 1 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Ireland |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1930
Suffolk, Massachusetts
Son, age 12
Suffolk, Massachusetts · implied b. ~1918 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Leonard |
| Given Name | John S. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Canada English |
| Occupation | none |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Suffolk-County, Massachusetts
Son, age 22
Suffolk-County, Massachusetts · implied b. ~1918 — 6 household members
| Surname | Leonard |
| Given Name | John |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 22 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| Occupation | Helper |
| Industry | Printing Co. |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 296 |
| Highest Grade | Hs 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 Leonard across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father Melvin Leonard (~0.92 confidence) and mother Mabel Leonard (~0.92 confidence) and mother Catherine Leonard (~0.92 confidence) and mother Catherine Leonard (~0.92 confidence) and father John Leonard (~0.92 confidence). The pedigree spans 1 generation with 5 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
Melvin Leonard
b. ~1879
Source father
● Household
· direct · ~0.92
Mother
Mabel Leonard
b. ~1879
Source mother
● Household
· direct · ~0.92
Mother
Catherine Leonard
b. ~1884
Source mother
● Household
· direct · ~0.92
Mother
Catherine Leonard
b. ~1889
Source mother
● Household
· direct · ~0.92
Father
John Leonard
b. ~1891
Source father
● Household
· direct · ~0.92
This person
Anchor record
John Leonard
Son · 1940 · age 22 · b. ~1918 · Massachusetts
★ You are viewing this record
Sibling
Mary Leonard
Sibling · 1940 · age 26
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Leonard
Sibling · 1940 · age 28
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Katherine Leonard
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Edward Leonard
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 — 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-t0627-01669-00186)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Duffy Mathilda Conti | 45 | Head | — | Same House |
| 42 | Dorothy Conti | 15 | Daughter | — | Massachusetts |
| 43 | Dami Albert Conti | 53 | Brother-in-law | Painter | Canada |
| 44 | Mary Petrie | 71 | Head | — | Canada |
| 45 | Alice Connell | 67 | Lodger | — | Hong Kong |
| 46 | John Costello | 65 | Head | — | Italy |
| 47 | Margaret Costello | 63 | Wife | — | Irish Free State |
| 48 | Thomas Costello | 31 | Son | Clerk, File | Massachusetts |
| 49 | Peter Costello | 26 | Son | Mover | Massachusetts |
| 50 | Mary Costello | 23 | Daughter | Clerk, Sales | Massachusetts |
| 51 | John Degiacomo | 49 | Head | Operator | Lithuania |
| 52 | Rose Degiacomo | 47 | Wife | Cleaner | Lithuania |
| 53 | Albert Degiacomo | 21 | Son | Stock Clerk | Massachusetts |
| 54 | Alice Degiacomo | 15 | Daughter | — | Massachusetts |
| 55 | James Cunningham | 26 | Head | Confectioner | Massachusetts |
| 56 | Harriet Cunningham | 21 | Wife | Waitress | Massachusetts |
| 57 | Ignatius Greene | 50 | Head | Laborer | Ireland |
| 58 | Adella Greene | 48 | Wife | Helper | Ireland |
| 59 | Edward Greene | 21 | Son | Laborer | Massachusetts |
| 60 | Amanda Greene | 16 | Daughter | — | Massachusetts |
| 61 | Estella Greene | 12 | Daughter | — | Massachusetts |
| 62 | George Maguire | 47 | Head | Pipe Fitter | Massachusetts |
| 63 | Adell Maguire | 50 | Wife | — | Massachusetts |
| 64 | Geraldine Maguire | 20 | Daughter | Inspector | Massachusetts |
| 65 | Virginia Maguire | 18 | Daughter | Inspector | Massachusetts |
| 66 | George Jr. Maguire | 15 | Son | — | Massachusetts |
| 67 | Phyllis Maguire | 14 | Daughter | — | Massachusetts |
| 68 | Evelyn Maguire | 13 | Daughter | — | Massachusetts |
| 69 | John Maguire | 11 | Son | — | Massachusetts |
| 70 | Catherine Leonard | 56 | Head | — | Irish Free State |
| 71 | James Leonard | 28 | Son | Shipper | Massachusetts |
| 72 | Mary Leonard | 26 | Daughter | Saleslady | Massachusetts |
| 73 | John Leonard THIS PERSON | 22 | Son | Helper | Massachusetts |
| 74 | Edward Leonard | 18 | Son | — | Massachusetts |
| 75 | Katherine Leonard | 16 | Daughter | — | Massachusetts |
| 76 | William Fallon | 70 | Head | Janitor | Irish Free State |
| 77 | Mary Fallon | 59 | Wife | — | Irish Free State |
| 78 | Charles Fallon | 27 | Son | Mail Clerk | Massachusetts |
| 79 | John Fallon | 23 | Son | Pressman | Massachusetts |
| 80 | Mary Fallon | 20 | Daughter | Telephone Oper. | Massachusetts |
Pedigree Summary
John + 4 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 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)