JC
James Costello — 1940 US Census Record
Linked across censuses1940 United States Federal Census · San-Francisco-County, California
Our Model Tree links this James Costello across the 1930 and 1940 US Censuses in San-Francisco-County, California (XGBoost, ~Confirmed) — first a son (b.~1930), then head of a 8-person household.
Age 10
b. ~1930
Male
Son
Born: California
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | San-Francisco-County, California |
| Surname | Costello |
| Given Name | James |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 10 |
| Marital Status | Single |
| Birthplace | California |
| 1935 Residence (City) | San Francisco |
| 1935 Residence (County) | San Francisco |
| Additional Details | |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
| Township / Ward | San Francisco |
| Est. Birth Year | ~1930 |
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.
8 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to James | Age | Birth yr |
|---|---|---|---|---|
| John Costello | Son | — | 12 | ~1928 |
| Marguerite Costello | Spouse | — | 39 | ~1901 |
| Robert Costello | Son | — | 13 | ~1927 |
| Donald Costello | Son | — | 4 | ~1936 |
| Patricia Costello | Daughter | — | 14 | ~1926 |
| Robert Costello | Head | — | 41 | ~1899 |
| Raymond Costello | Son | — | 8 | ~1932 |
| James Costello | Son | — | 10 | ~1930 |
Census Appearances
1930
San Francisco, …
Son, age
San Francisco, California · implied b. ~1930 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Costello |
| Given Name | James E. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 0 |
| Marital Status | Single |
| Birthplace | California |
| Father's Birthplace | North Ireland |
| Mother's Birthplace | California |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
1940
San-Francisco-County, California
Son, age 10
San-Francisco-County, California · implied b. ~1930 — 8 household members
| Surname | Costello |
| Given Name | James |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 10 |
| Marital Status | Single |
| Birthplace | California |
| 1935 Residence (City) | San Francisco |
| 1935 Residence (County) | San Francisco |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
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 James Costello across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
James Costello
Son · 1940 · age 10 · b. ~1930 · California
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Sibling
Donald Costello
Sibling · 1940 · age 4
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Robert Costello
Sibling · 1940 · age 13
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Raymond Costello
Sibling · 1940 · age 8
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
John Costello
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Patricia Costello
Sibling · 1940 · age 14
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 — San-Francisco-County, California
Open full size
1940 US Federal Census — San-Francisco-County, California
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00316-00630)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Alexis Andler | 67 | Head | — | California |
| 2 | Virginia Andler | 65 | Sister | — | California |
| 3 | Maurice Clark | 50 | Head | Porter | Vermont |
| 4 | Mary Clark | 52 | Wife | Linen Clerk | Eire |
| 5 | Maurice Jr. Clark | 25 | Son | Pipe-Fitter | California |
| 6 | James Carr | 22 | Head | Manager | Missouri |
| 7 | Lorraine Carr | 19 | Wife | — | Nebraska |
| 8 | Philip Spinas | 39 | Head | Saw Filer | California |
| 9 | Janet Spinas | 35 | Wife | — | California |
| 10 | Evaline Norton | 70 | Wife's mother | — | California |
| 11 | Orville Thompson | 32 | Head | Barber | Mexico |
| 12 | Faye Thompson | 26 | Wife | — | Iowa |
| 13 | John German | 29 | Head | Metal Polisher | Kansas |
| 14 | Elna German | 23 | Wife | — | Canada |
| 15 | William German | 1 | Son | — | California |
| 16 | Robert Costello | 41 | Head | Lineman | Eire |
| 17 | Marguerite Costello | 39 | Wife | — | California |
| 18 | Patricia Costello | 14 | Daughter | — | California |
| 19 | Robert Jr. Costello | 13 | Son | — | California |
| 20 | John Costello | 12 | Son | — | California |
| 21 | James Costello THIS PERSON | 10 | Son | — | California |
| 22 | Raymond Costello | 8 | Son | — | California |
| 23 | Donald Costello | 4 | Son | — | California |
| 24 | Edwin Mann | 36 | Head | Technician | California |
| 25 | Julia Mann | 39 | Wife | — | Minnesota |
| 26 | Gary Mann | 6 | Son | — | California |
| 27 | Patricia Mann | 4 | Daughter | — | California |
| 28 | Chris Mitchell | 38 | Head | Salesman | California |
| 29 | Bernadette Hluggan | 25 | Sister | Secretary | California |
| 30 | John Hluggan | 26 | Bro-in-law | Statistician | California |
| 31 | Margaret Lally | 54 | Head | White Clerk | California |
| 32 | Katherine Lally | 52 | Sister | Comptometer Operator | California |
| 33 | Kate Roberts | 68 | Head | Janitress | Nevada |
| 34 | John Trudrung | 20 | Grandson | New Worker | California |
| 35 | Ellen Freeman | 27 | Head | Saleslady | California |
| 36 | Jacqueline Freeman | 9 | Daughter | — | California |
| 37 | Barbara Freeman | 7 | Daughter | — | California |
| 38 | Armatiede O'Quinn | 77 | Lodger | — | Louisiana |
| 39 | Christian Peetz | 54 | Head | Watchmaker | Germany |
| 40 | Nettie Peetz | 52 | Wife | — | California |
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)