MC
Mary Costello — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Suffolk-County, Massachusetts
Our Model Tree links this Mary Costello across the 1930 and 1940 US Censuses in Suffolk-County, Massachusetts (XGBoost, ~Confirmed) — first a daughter (b.~1924), then head of a 11-person household.
Age 16
b. ~1924
Female
Daughter
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Suffolk-County, Massachusetts |
| Surname | Costello |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 16 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| Additional Details | |
| Industry | 0 |
| Highest Grade | H 2 |
| 1935 Residence | Same House |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Township / Ward | Boston City |
| Est. Birth Year | ~1924 |
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.
11 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Agnes Costello | Daughter | — | 11 | ~1929 |
| Mary Costello | Daughter | — | 16 | ~1924 |
| Frances Costello | Daughter | — | 2 | ~1938 |
| Catherine Costello | Daughter | — | 12 | ~1928 |
| John Costello | Head | — | 42 | ~1898 |
| Joseph Costello | Son | — | 14 | ~1926 |
| Lawrence Costello | Son | — | 9 | ~1931 |
| John Costello | Son | — | 10 | ~1930 |
| James Costello | Son | — | 4 | ~1936 |
| Thomas Costello | Son | — | 6 | ~1934 |
| Harriett Costello | Spouse | — | 40 | ~1900 |
Census Appearances
1930
Suffolk, Massachusetts
Daughter, age 6
Suffolk, Massachusetts · implied b. ~1924 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Costello |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 6 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Italy |
| Mother's Birthplace | Italy |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Suffolk-County, Massachusetts
Daughter, age 16
Suffolk-County, Massachusetts · implied b. ~1924 — 11 household members
| Surname | Costello |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 16 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Boston City |
| 1935 Residence (County) | Suffolk |
| Industry | 0 |
| Highest Grade | H 2 |
| 1935 Residence | Same House |
| 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 Mary Costello across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Costello
Daughter · 1940 · age 16 · b. ~1924 · Massachusetts
★ You are viewing this record
Sibling
Agnes Costello
Sibling · 1940 · age 11
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Costello
Sibling · 1940 · age 4
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Joseph Costello
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Frances Costello
Sibling · 1940 · age 2
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Lawrence Costello
Sibling · 1940 · age 9
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Catherine Costello
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Thomas Costello
Sibling · 1940 · age 6
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
John Costello
Sibling · 1940 · age 10
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-t0627-01669-00748)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Anna B. Coleman | 38 | Wife | — | Massachusetts |
| 2 | Martin F. Coleman | 14 | Son | — | Massachusetts |
| 3 | Anne Coleman | 13 | Daughter | — | Massachusetts |
| 4 | Richard Coleman | 8 | Son | — | Massachusetts |
| 5 | Robert Coleman | 6 | Son | — | Massachusetts |
| 6 | Mary Ryder | 47 | Head | Matron | Irish Free State |
| 7 | Esther A. Ryder | 21 | Daughter | Salesgirl | Massachusetts |
| 8 | Doris Ryder | 17 | Daughter | — | Massachusetts |
| 9 | Geraldine Ryder | 14 | Daughter | — | Massachusetts |
| 10 | Joseph Ryder | 12 | Son | — | Massachusetts |
| 11 | Mae Smith | 44 | Head | — | Massachusetts |
| 12 | Florence Smith | 23 | Daughter | Egg Handler | Massachusetts |
| 13 | Virginia Smith | 22 | Daughter | Assembler | Massachusetts |
| 14 | James Smith | 16 | Son | — | Massachusetts |
| 15 | Charles Randall | 9 | Lodger | — | Massachusetts |
| 16 | James Hennessey | 60 | Lodger | Laborer | Massachusetts |
| 17 | John B. Costello | 42 | Head | Street Car Operator | Irish Free State |
| 18 | Harriett Costello | 40 | Wife | — | Massachusetts |
| 19 | Mary Costello THIS PERSON | 16 | Daughter | — | Massachusetts |
| 20 | Joseph P. Costello | 14 | Son | — | Massachusetts |
| 21 | Catherine Costello | 12 | Daughter | — | Massachusetts |
| 22 | Agnes Costello | 11 | Daughter | — | Massachusetts |
| 23 | John Jr. Costello | 10 | Son | — | Massachusetts |
| 24 | Lawrence Costello | 9 | Son | — | Massachusetts |
| 25 | Thomas Costello | 6 | Son | — | Massachusetts |
| 26 | James Costello | 4 | Son | — | Massachusetts |
| 27 | Frances Costello | 2 | Daughter | — | Massachusetts |
| 28 | John Mitchell | 44 | Head | Laborer | Irish Free State |
| 29 | Delia Mitchell | 31 | Wife | — | Irish Free State |
| 30 | Nora Mitchell | 6 | Daughter | — | Massachusetts |
| 31 | Mary Mitchell | 4 | Daughter | — | Massachusetts |
| 32 | Edward Hudson | 48 | Head | Fireman | Massachusetts |
| 33 | Harriet A. Hudson | 48 | Wife | — | Massachusetts |
| 34 | Edna Hudson | 18 | Daughter | New Worker | Massachusetts |
| 35 | Ruth Hudson | 13 | Daughter | — | Massachusetts |
| 36 | Barbara Hudson | 10 | Daughter | — | Massachusetts |
| 37 | John J. O'Leary | 58 | Head | Cooper | Irish Free State |
| 38 | Mary B. O'Leary | 53 | Wife | — | Massachusetts |
| 39 | Margaret O'Leary | 24 | Daughter | Administrator | Massachusetts |
| 40 | Dorothy O'Leary | 22 | Daughter | Stenographer | Massachusetts |
Related Census Records
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)