MC
Mary Costa — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Alameda-County, California
Our Model Tree links this Mary Costa across the 1930 and 1940 US Censuses in Alameda-County, California (XGBoost, ~Confirmed) — first a spouse (b.~1903), then head of a 8-person household.
Age 37
b. ~1903
Female
Spouse
Born: Hawaii
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Alameda-County, California |
| Surname | Costa |
| Given Name | Mary |
| Relationship to Head | wife |
| Sex | F |
| Color / Race | White |
| Age | 37 |
| Marital Status | Married |
| Birthplace | Hawaii |
| 1935 Residence (City) | Oakland |
| 1935 Residence (County) | Alameda |
| Additional Details | |
| Occupation | H |
| Industry | S |
| Highest Grade | 8 |
| 1935 Residence | California |
| Birth State | Hawaii |
| Birth Country | United States |
| Birthplace (normalized) | hawaii |
| Occupation | H |
| Township / Ward | Eden Twp |
| Est. Birth Year | ~1903 |
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 Mary | Age | Birth yr |
|---|---|---|---|---|
| Mary Costa | Spouse | — | 37 | ~1903 |
| Rosaline Costa | Daughter | — | 12 | ~1928 |
| Raymond Costa | Son | — | 2 | ~1938 |
| Helen Costa | Daughter | — | 5 | ~1935 |
| Joseph Costa | Son | — | 15 | ~1925 |
| Frances Costa | Daughter | — | 9 | ~1931 |
| Betty Costa | Daughter | — | 6 | ~1934 |
| Marie Costa | Daughter | — | 13 | ~1927 |
Census Appearances
1930
Alameda, California
Other, age 27
Alameda, California · implied b. ~1903 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Costa |
| Given Name | Mary |
| Relationship to Head | Wife-H |
| Sex | F |
| Color / Race | White |
| Age | 27 |
| Marital Status | Married |
| Birthplace | Hawaii |
| Naturalization Status | Naturalized |
| Year of Immigration | 1914 |
| Age at First Marriage | 17 |
| Father's Birthplace | Portugal |
| Mother's Birthplace | Hawaii |
| Can Read/Write | Yes |
| Mother Tongue | Portuguese |
| Birth State | Hawaii |
| Birth Country | United States |
| Birthplace (normalized) | hawaii |
1940
Alameda-County, California
Spouse, age 37
Alameda-County, California · implied b. ~1903 — 8 household members
| Surname | Costa |
| Given Name | Mary |
| Relationship to Head | wife |
| Sex | F |
| Color / Race | White |
| Age | 37 |
| Marital Status | Married |
| Birthplace | Hawaii |
| 1935 Residence (City) | Oakland |
| 1935 Residence (County) | Alameda |
| Occupation | H |
| Industry | S |
| Highest Grade | 8 |
| 1935 Residence | California |
| Birth State | Hawaii |
| Birth Country | United States |
| Birthplace (normalized) | hawaii |
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 Costa across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Costa
Spouse · 1940 · age 37 · b. ~1903 · California
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Confirmed / household (~0.90+)
Probable / derived (~0.65–0.89)
Candidate (<0.65, unverified)
Original Census Page
1940 US Federal Census — Alameda-County, California
Open full size
1940 US Federal Census — Alameda-County, California
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00185-00090)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Mary Costa THIS PERSON | 37 | wife | H | Hawaii |
| 2 | Joseph Costa | 15 | son | Wood Worker | California |
| 3 | Marie Costa | 13 | daughter | — | California |
| 4 | Rosaline Costa | 12 | daughter | — | California |
| 5 | Frances Costa | 9 | daughter | — | California |
| 6 | Betty Mae Costa | 6 | daughter | — | California |
| 7 | Helen Costa | 5 | daughter | — | California |
| 8 | Raymond Costa | 2 | son | — | California |
| 9 | Raymond Lawless | 37 | head | Plumber | Nebraska |
| 10 | Nettie Lawless | 39 | wife | H | Iowa |
| 11 | Charlotte Lawless | 16 | daughter | — | Oregon |
| 12 | Kay Lawless | 14 | son | — | Colorado |
| 13 | Marjorie Lawless | 9 | daughter | — | California |
| 14 | Roland Lawless | 7 | son | — | California |
| 15 | Patricia Lawless | 2 | daughter | — | California |
| 16 | Winifred P. Allen | 32 | head | Sales & Service | Washington |
| 17 | Vera Allen | 34 | wife | H | California |
| 18 | Laura Allen | 10 | daughter | — | California |
| 19 | Louis Allen | 10 | daughter | — | California |
| 20 | Jesse A. Allen | 52 | father | Auto Salesman | Kansas |
| 21 | Albert D. Gommerman | 69 | head | U | Missouri |
| 22 | Leila M. Gommerman | 61 | wife | H | California |
| 23 | Jack Crandall | 24 | head | Assembler | Utah |
| 24 | Twila Crandall | 33 | wife | H | Utah |
| 25 | Janice Crandall | 2 | daughter | — | California |
| 26 | John Crandall | 1 | son | — | California |
| 27 | Rhinehold Diefenbaugh | 45 | head | U | Indiana |
| 28 | Doris Diefenbaugh | 47 | wife | H | California |
| 29 | Charles Cobert | 27 | head | Truck Driver | Ohio |
| 30 | Mary Cobert | 26 | wife | H | Ohio |
| 31 | Louise M. Cobert | 3 | daughter | — | California |
| 32 | Roberta J. Cobert | 2 | daughter | — | California |
| 33 | Jacob Jacobson | 45 | head | Seaman | Norway |
| 34 | Julia Jacobson | 43 | wife | H | Washington |
| 35 | James Johnstone | 43 | cousin | Seaman | Oregon |
| 36 | Clifford Holderman | 36 | head | Warehouseman | Kansas |
| 37 | Mary Holderman | 34 | wife | H | Oklahoma |
| 38 | Ethel Holderman | 14 | sister | S | Oklahoma |
| 39 | Samuel Hilliard | 60 | head | Plumber | Michigan |
| 40 | Eilene Hilliard | 37 | wife | H | Michigan |
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)