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Mary Blackwell — 1940 US Census Record
Linked across censuses1940 United States Federal Census · District-Of-Columbia-County, District of Columbia
Our Model Tree links this Mary Blackwell across the 1930 and 1940 US Censuses in District-Of-Columbia-County, District of Columbia (XGBoost, ~Confirmed) — first a spouse (b.~1901), then head of a 12-person household.
Age 39
b. ~1901
Female
Spouse
Born: Virginia
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | District-Of-Columbia-County, District of Columbia |
| Surname | Blackwell |
| Given Name | Mary K. |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 39 |
| Marital Status | Married |
| Birthplace | Virginia |
| 1935 Residence (City) | Washington |
| 1935 Residence (County) | District Of Columbia |
| Additional Details | |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | Virginia |
| Birth Country | United States |
| Birthplace (normalized) | virginia |
| Township / Ward | Washington |
| Est. Birth Year | ~1901 |
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.
12 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Evelyn Blackwell | Daughter | — | 19 | ~1921 |
| Mary Blackwell | Spouse | — | 39 | ~1901 |
| Carl Blackwell | Son | — | 14 | ~1926 |
| Jack Blackwell | Son | — | 4 | ~1936 |
| Bettie Blackwell | Daughter | — | 8 | ~1932 |
| Robbie Blackwell | Son | — | 1 | ~1939 |
| Jimmie Blackwell | Son | — | ~1940 | |
| Shirley Blackwell | Daughter | — | 6 | ~1934 |
| George Blackwell | Head | — | 42 | ~1898 |
| Georgia Blackwell | Daughter | — | 17 | ~1923 |
| Thomas Blackwell | Son | — | 10 | ~1930 |
| Una Blackwell | Daughter | — | 11 | ~1929 |
Census Appearances
1930
District Of …
Other, age 29
District Of Columbia, District of Columbia · implied b. ~1901 — 11 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Blackwell |
| Given Name | Mary |
| Relationship to Head | Sis-in-law |
| Sex | F |
| Color / Race | Black |
| Age | 29 |
| Marital Status | Married |
| Birthplace | Virginia |
| Age at First Marriage | 16 |
| Father's Birthplace | Virginia |
| Mother's Birthplace | Virginia |
| Occupation | Servant |
| Industry | Private family |
| Class of Worker | W |
| Can Read/Write | Yes |
| Birth State | Virginia |
| Birth Country | United States |
| Birthplace (normalized) | virginia |
1940
District-Of-Columbia-County, District …
Spouse, age 39
District-Of-Columbia-County, District of Columbia · implied b. ~1901 — 12 household members
| Surname | Blackwell |
| Given Name | Mary K. |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 39 |
| Marital Status | Married |
| Birthplace | Virginia |
| 1935 Residence (City) | Washington |
| 1935 Residence (County) | District Of Columbia |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | Virginia |
| Birth Country | United States |
| Birthplace (normalized) | virginia |
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 Blackwell across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
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This person
Anchor record
Mary Blackwell
Spouse · 1940 · age 39 · b. ~1901 · District of Columbia
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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 — District-Of-Columbia-County, District of Columbia
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1940 US Federal Census — District-Of-Columbia-County, District of Columbia
Page Contents
39 people indexed on this census page (nara:1940:m-t0627-00558-00992)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Margaret A. Smith | 56 | Wife | Clerk | Ohio |
| 42 | Elizabeth Lamphier | 33 | Daughter | Clerk | D.C. |
| 43 | Charles H. Lamphier | 4 | Grandson | — | D.C. |
| 44 | William M. Hessler | 29 | Son-in-law | Salesman | D.C. |
| 45 | Margaret Hessler | 26 | Daughter | — | D.C. |
| 46 | William H. Hessler | 2 | Grandson | — | D.C. |
| 48 | Rosa G. Weathersell | 60 | Head | — | South Carolina |
| 49 | Emeline Weathersell | 18 | Daughter | New Worker | D.C. |
| 50 | Charles P. Adams | 36 | Son-in-law | Electrician | Maryland |
| 51 | Elizabeth Adams | 30 | Daughter | — | D.C. |
| 52 | Charles P. Jr. Adams | 1 | Grandson | — | D.C. |
| 53 | Marian Mudd | 39 | Daughter | Scientist Assistant | South Carolina |
| 54 | Ethel Crawford | 33 | Daughter | File Clerk | South Carolina |
| 55 | George R. Crawford | 10 | Grandson | — | D.C. |
| 56 | Cecil L. Cain | 41 | Head | Machinist | Maine |
| 57 | Alice M. Cain | 34 | Wife | — | Scotland |
| 58 | Frederick A. Cain | 9 | Son | — | Connecticut |
| 59 | Nancy L. Cain | 1 | Daughter | — | D.C. |
| 60 | Alexina Summers | 62 | Mother-in-law | — | Scotland |
| 61 | Thomas F. Dyer | 76 | Head | — | New Jersey |
| 62 | Emily C. Dyer | 69 | Wife | — | New York |
| 63 | George G. Blackwell | 42 | Head | Iron Worker | Virginia |
| 64 | Mary K. Blackwell THIS PERSON | 39 | Wife | — | Virginia |
| 65 | Evelyn E. Blackwell | 19 | Daughter | File Clerk | West Virginia |
| 66 | Georgia E. Blackwell | 17 | Daughter | — | West Virginia |
| 67 | Carl D. Blackwell | 14 | Son | — | West Virginia |
| 68 | Una M. Blackwell | 11 | Daughter | — | West Virginia |
| 69 | Thomas E. Blackwell | 10 | Son | — | D.C. |
| 70 | Bettie J. Blackwell | 8 | Daughter | — | D.C. |
| 71 | Shirley Blackwell | 6 | Daughter | — | D.C. |
| 72 | Jack R. Blackwell | 4 | Son | — | D.C. |
| 73 | Robbie F. Blackwell | 1 | Son | — | D.C. |
| 74 | Jimmie L. Blackwell | 0 | Son | — | D.C. |
| 75 | James A. Hamby | 52 | Head | Electric Welder | Wisconsin |
| 76 | Cerelia Hamby | 49 | Wife | — | Missouri |
| 77 | Betty R. Hamby | 13 | Daughter | — | Oklahoma |
| 78 | Mary V. Hamby | 12 | Daughter | — | Oklahoma |
| 79 | Aubrey E. Dalton | 25 | Head | Laborer | Virginia |
| 80 | Katherine Dalton | 21 | Wife | — | Virginia |
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)