MC
Mary Cobb — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Fairfax-County, Virginia
Our Model Tree links this Mary Cobb across the 1930 and 1940 US Censuses in Fairfax-County, Virginia (XGBoost, ~Confirmed) — first a daughter (b.~1929), then head of a 9-person household.
Age 11
b. ~1929
Female
Daughter
Born: Virginia
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Fairfax-County, Virginia |
| Surname | Cobb |
| Given Name | Mary L. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 11 |
| Marital Status | Single |
| Birthplace | Virginia |
| 1935 Residence (City) | Fairfax |
| 1935 Residence (County) | Fairfax |
| Additional Details | |
| Highest Grade | 4 |
| 1935 Residence | Same place |
| Birth State | Virginia |
| Birth Country | United States |
| Birthplace (normalized) | virginia |
| Township / Ward | Fairfax |
| Est. Birth Year | ~1929 |
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.
9 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| James Cobb | Son | — | 5 | ~1935 |
| Mildred Cobb | Spouse | — | 41 | ~1899 |
| Melvin Cobb | Son | — | 16 | ~1924 |
| James Cobb | Head | — | 45 | ~1895 |
| Alice Cobb | Daughter | — | 12 | ~1928 |
| Edgar Cobb | Son | — | 17 | ~1923 |
| Bernice Cobb | Daughter | — | 9 | ~1931 |
| Lucille Cobb | Daughter | — | 3 | ~1937 |
| Mary Cobb | Daughter | — | 11 | ~1929 |
Census Appearances
1930
Fairfax, Virginia
Daughter, age
Fairfax, Virginia · implied b. ~1930 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Cobb |
| Given Name | Mary L. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 0 |
| Marital Status | Single |
| Birthplace | Virginia |
| Father's Birthplace | Virginia |
| Mother's Birthplace | Virginia |
| Occupation | none |
| Birth State | Virginia |
| Birth Country | United States |
| Birthplace (normalized) | virginia |
1940
Fairfax-County, Virginia
Daughter, age 11
Fairfax-County, Virginia · implied b. ~1929 — 9 household members
| Surname | Cobb |
| Given Name | Mary L. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 11 |
| Marital Status | Single |
| Birthplace | Virginia |
| 1935 Residence (City) | Fairfax |
| 1935 Residence (County) | Fairfax |
| Highest Grade | 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 Cobb across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Cobb
Daughter · 1940 · age 11 · b. ~1929 · Virginia
★ You are viewing this record
Sibling
James Cobb
Sibling · 1940 · age 5
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Alice Cobb
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Bernice Cobb
Sibling · 1940 · age 9
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Lucille Cobb
Sibling · 1940 · age 3
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Edgar Cobb
Sibling · 1940 · age 17
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Melvin Cobb
Sibling · 1940 · age 16
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 — Fairfax-County, Virginia
Open full size
1940 US Federal Census — Fairfax-County, Virginia
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-04261-00079)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Sparks Blanche F. (X) Sparks | 23 | Wife | — | Virginia |
| 2 | Johnie H. Sparks | 3 | Son | — | Virginia |
| 3 | Carolyn R. Sparks | 1 | Daughter | — | Virginia |
| 4 | J. Edward Anderson | 72 | Head | Farmer | Virginia |
| 5 | J. Garner (X) Wilson | 20 | Lodger | Carpenters Helper | Virginia |
| 6 | Clara L. (X) Wilson | 16 | Lodger | — | Virginia |
| 7 | Shelton Slewing | 44 | Head | Laborer | Virginia |
| 8 | Faithie M. Slewing | 49 | Wife | — | Virginia |
| 9 | Albert W. Slewing | 20 | Son | Laborer | Virginia |
| 10 | Cecil H. Slewing | 16 | Daughter | — | Virginia |
| 11 | Harry G. Robey | 31 | Head | Carpenter | Virginia |
| 12 | Lillah S. (X) Robey | 26 | Wife | — | Virginia |
| 13 | Carl H. Robey | 8 | Son | — | Virginia |
| 14 | Norman R. Robey | 5 | Son | — | Virginia |
| 15 | James E. Robey | 2 | Son | — | Virginia |
| 16 | Clarence R. Blevins | 30 | Head | Patrolman | Virginia |
| 17 | Virginia (X) Blevins | 21 | Wife | — | Virginia |
| 18 | Juanita Blevins | 2 | Daughter | — | Virginia |
| 19 | Thurman B. Dalrymple | 6 | Step-son | — | Virginia |
| 20 | Rubin G. Dalrymple | 5 | Step-son | — | Virginia |
| 21 | Gary R. Dalrymple | 4 | Step-son | — | Virginia |
| 22 | James H. (X) Cobb | 45 | Head | Farmer | North Carolina |
| 23 | Mildred (X) Cobb | 41 | Wife | — | Virginia |
| 24 | Edgar F. Cobb | 17 | Son | — | Virginia |
| 25 | Melvin L. Cobb | 16 | Son | — | Virginia |
| 26 | Alice G. Cobb | 12 | Daughter | — | Virginia |
| 27 | Mary L. Cobb THIS PERSON | 11 | Daughter | — | Virginia |
| 28 | Bernice M. Cobb | 9 | Daughter | — | Virginia |
| 29 | James Cobb | 5 | Son | — | Virginia |
| 30 | Lucille J. Cobb | 3 | Daughter | — | Virginia |
| 31 | William R. Johnson | 65 | Head | Farm Hand | Virginia |
| 32 | Lucy M. (X) Johnson | 56 | Wife | — | Virginia |
| 33 | Jerome P. Johnson | 28 | Son | Well Digger | Virginia |
| 34 | Blanche G. Johnson | 20 | Daughter-in-law | — | Virginia |
| 35 | Frederick L. Johnson | 5 | Grand-son | — | Virginia |
| 36 | Shellie M. Johnson | 4 | Grand-daughter | — | Virginia |
| 37 | Payton M. Johnson | 3 | Grand-son | — | Virginia |
| 38 | Elliot W. Johnson | 2 | Grand-son | — | Virginia |
| 39 | William A. Johnson | 1 | Son | — | Virginia |
| 40 | Sandra L. Johnson | 0 | Grand-daughter | — | 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)