MC
Margaret Callahan — 1940 US Census Record
Model Tree available1940 United States Federal Census · Middlesex-County, Massachusetts
Our Model Tree links this Margaret Callahan across the 1920, 1930 and 1940 US Censuses in Middlesex-County, Massachusetts (XGBoost, ~Confirmed), with identified parents Thomas & Thomas — first a daughter (b.~1915), then head of a 3-person household.
Age 25
b. ~1915
Female
Daughter
Born: At Sea
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Middlesex-County, Massachusetts |
| Surname | Callahan |
| Given Name | Margaret |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | At Sea |
| 1935 Residence (City) | Waltham |
| 1935 Residence (County) | Middlesex |
| Naturalization Status | Naturalized |
| Additional Details | |
| Occupation | Reg. Nurse |
| Industry | Private hospital |
| Class of Worker | PW |
| Hours Worked | 30 |
| Income (1939) | 1369 |
| Highest Grade | H-4 |
| 1935 Residence | Same place |
| Birthplace (normalized) | at sea |
| Occupation | Reg. Nurse |
| Township / Ward | Waltham |
| Est. Birth Year | ~1915 |
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.
3 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Margaret | Age | Birth yr |
|---|---|---|---|---|
| Margaret Callahan | Daughter | — | 25 | ~1915 |
| Mary Callahan | Head | — | 52 | ~1888 |
| Ruth Callahan | Daughter | — | 21 | ~1919 |
Census Appearances
1920
Middlesex, Massachusetts
Daughter, age 3
Middlesex, Massachusetts · implied b. ~1917 — 4 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Callahan |
| Given Name | Margaret |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 3 |
| Marital Status | Single |
| Birthplace | At Sea |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Occupation | none |
| Mother Tongue | English |
| Birthplace (normalized) | at sea |
1930
Middlesex, Massachusetts
Daughter, age 13
Middlesex, Massachusetts · implied b. ~1917 — 9 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Callahan |
| Given Name | Margaret M. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 13 |
| Marital Status | Single |
| Birthplace | At sea |
| Naturalization Status | Naturalized |
| Year of Immigration | 1916 |
| Father's Birthplace | Irish Free State |
| Mother's Birthplace | Irish Free State |
| Occupation | none |
| Can Read/Write | Yes |
| Mother Tongue | English |
| Birthplace (normalized) | at sea |
1940
Middlesex-County, Massachusetts
Daughter, age 25
Middlesex-County, Massachusetts · implied b. ~1915 — 3 household members
| Surname | Callahan |
| Given Name | Margaret |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | At Sea |
| 1935 Residence (City) | Waltham |
| 1935 Residence (County) | Middlesex |
| Naturalization Status | Naturalized |
| Occupation | Reg. Nurse |
| Industry | Private hospital |
| Class of Worker | PW |
| Hours Worked | 30 |
| Income (1939) | 1369 |
| Highest Grade | H-4 |
| 1935 Residence | Same place |
| Birthplace (normalized) | at sea |
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 Margaret Callahan across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father Thomas Callahan (~0.92 confidence) and father Thomas Callahan (~0.92 confidence) and mother Mary Callahan (~0.92 confidence) and mother Mary Callahan (~0.92 confidence). The pedigree spans 1 generation with 4 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
Thomas Callahan
b. ~1892
Source father
● Household
· direct · ~0.92
Father
Thomas Callahan
b. ~1892
Source father
● Household
· direct · ~0.92
Mother
Mary Callahan
b. ~1889
Source mother
● Household
· direct · ~0.92
Mother
Mary Callahan
b. ~1888
Source mother
● Household
· direct · ~0.92
This person
Anchor record
Margaret Callahan
Daughter · 1940 · age 25 · b. ~1915 · Massachusetts
★ You are viewing this record
Sibling
Ruth Callahan
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 — 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-t0627-01619-00639)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Millie Johnson | 55 | Head | Secretary | Vermont |
| 42 | Eleanor Johnson | 15 | Daughter | — | New Hampshire |
| 43 | Walter Spinney | 64 | Head | Mach. Operator | Maine |
| 44 | Ella Spinney | 64 | Wife | — | Canada |
| 45 | Louis Perilli | 53 | Head | Machinist | Italy |
| 46 | Susie Perilli | 43 | Wife | — | Italy |
| 47 | Charles Perilli | 27 | Son | Mach. Helper | Mass. |
| 48 | Catherine Perilli | 25 | Daughter | Mach. Oper. | Mass. |
| 49 | James King | 58 | Head | Painter | Mass. |
| 50 | Lillian King | 56 | Sister | Ward Worker | Mass. |
| 51 | Hazel Macdonough | 32 | Cousin | Assembler | California |
| 52 | Annie Mcmanus | 65 | Aunt | — | Mass. |
| 53 | George Henry | 47 | Head | Chauffeur | England |
| 54 | Edith Henry | 44 | Wife | — | Mass. |
| 55 | Wayne Henry | 5 | Son | — | Mass. |
| 56 | George Jr. Henry | 4 | Son | — | Mass. |
| 57 | Arthur Kelley | 34 | Head | Mechanic | Vermont |
| 58 | Dorothy Kelley | 32 | Wife | — | Mass. |
| 59 | Shirley May Kelley | 13 | Daughter | — | Mass. |
| 60 | Paul Leon Kelley | 8 | Son | — | Mass. |
| 61 | Richard M. Kelley | 2 | Son | — | Mass. |
| 62 | John Connolly | 36 | Head | Roper Maker | Mass. |
| 63 | Elizabeth Connolly | 35 | Wife | — | Mass. |
| 64 | Doris Connolly | 5 | Daughter | — | Mass. |
| 65 | John Connolly | 13 | Son | — | Mass. |
| 66 | Gustave Benson | 53 | Head | Mechanic | Sweden |
| 67 | Helen Benson | 53 | Wife | — | Mass. |
| 68 | Paul Benson | 21 | Son | Tire Worker | Mass. |
| 69 | Norma Benson | 19 | Daughter | Mach. Oper. | Mass. |
| 70 | Roy Benson | 12 | Son | — | Mass. |
| 71 | George Clasby | 43 | Head | Machinist | Mass. |
| 72 | Nellie Clasby | 34 | Wife | — | Mass. |
| 73 | Louise Clasby | 11 | Daughter | — | Mass. |
| 74 | George Clasby | 9 | Son | — | Mass. |
| 75 | David Clasby | 6 | Son | — | Mass. |
| 76 | Eugene Clasby | 1 | Son | — | Mass. |
| 77 | William Bennett | 23 | Lodger | Manager | Mass. |
| 78 | Mary Callahan | 52 | Head | — | Eire |
| 79 | Margaret Callahan THIS PERSON | 25 | Daughter | Reg. Nurse | At Sea |
| 80 | Ruth Marie Callahan | 21 | Daughter | Office Clerk | Mass. |
Pedigree Summary
Margaret + 1 sibling
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)