RD
Robert Duncan — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Mendocino-County, California
Our Model Tree links this Robert Duncan across the 1930 and 1940 US Censuses in Mendocino-County, California (XGBoost, ~Confirmed) — first a son (b.~1921), then head of a 8-person household.
Age 19
b. ~1921
Male
Son
Born: California
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Mendocino-County, California |
| Surname | Duncan |
| Given Name | Robert |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 19 |
| Marital Status | Single |
| Birthplace | California |
| 1935 Residence (City) | Round Valley Judicial |
| 1935 Residence (County) | Mendocino |
| Additional Details | |
| Hours Worked | 36 |
| Highest Grade | No 7 |
| 1935 Residence | Same place |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
| Township / Ward | Round Valley Judicial |
| Est. Birth Year | ~1921 |
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 Robert | Age | Birth yr |
|---|---|---|---|---|
| Robert Duncan | Son | — | 19 | ~1921 |
| Mary Duncon | Spouse | — | 48 | ~1892 |
| Arthur Duncan | Son | — | 22 | ~1918 |
| Owena Duncan | Daughter | — | 16 | ~1924 |
| Harry Henthorn | Son | — | 25 | ~1915 |
| Ivan Duncan | Son | — | 20 | ~1920 |
| Thelma Duncan | Daughter | — | 19 | ~1921 |
| Arva Duncan | Daughter | — | 5 | ~1935 |
Census Appearances
1930
Mendocino, California
Son, age 9
Mendocino, California · implied b. ~1921 — 7 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Duncan |
| Given Name | Robert L. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | American Indian |
| Age | 9 |
| Marital Status | Single |
| Birthplace | California |
| Father's Birthplace | Mixed Blood |
| Mother's Birthplace | Hatun |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
1940
Mendocino-County, California
Son, age 19
Mendocino-County, California · implied b. ~1921 — 8 household members
| Surname | Duncan |
| Given Name | Robert |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 19 |
| Marital Status | Single |
| Birthplace | California |
| 1935 Residence (City) | Round Valley Judicial |
| 1935 Residence (County) | Mendocino |
| Hours Worked | 36 |
| Highest Grade | No 7 |
| 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 Robert Duncan across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Robert Duncan
Son · 1940 · age 19 · b. ~1921 · California
★ You are viewing this record
Sibling
Ivan Duncan
Sibling · 1940 · age 20
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Thelma Duncan
Sibling · 1940 · age 19
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Arva Duncan
Sibling · 1940 · age 5
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Owena Duncan
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Arthur Duncan
Sibling · 1940 · age 22
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Harry Henthorn
Sibling · 1940 · age 25
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 — Mendocino-County, California
Open full size
1940 US Federal Census — Mendocino-County, California
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00263-00296)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Mary Duncon | 48 | Wife | — | California |
| 2 | Harry F Henthorn | 25 | Son | Laborer | California |
| 3 | Arthur E Duncan | 22 | Son | Laborer | California |
| 4 | Ivan Duncan | 20 | Son | Laborer | California |
| 5 | Robert Duncan THIS PERSON | 19 | Son | — | California |
| 6 | Thelma Mary Duncan | 19 | Daughter | Kitchen Helper | California |
| 7 | Owena J Duncan | 16 | Daughter | — | California |
| 8 | Arva Jean Duncan | 5 | Daughter | — | California |
| 9 | Alfred Brown | 68 | Head | — | California |
| 10 | Phena L Willits | 45 | Head | Farmer | California |
| 11 | Glenn R Willits | 23 | Son | Laborer | California |
| 12 | Elsie Willits | 22 | Daughter | — | California |
| 13 | Inis P Willits | 21 | Daughter | Laborer | California |
| 14 | Walter W Willits | 18 | Son | Laborer | California |
| 15 | Elizabeth Willits | 16 | Daughter | New Worker | California |
| 16 | George Willits | 14 | Son | — | California |
| 17 | Laura Willits | 13 | Daughter | — | California |
| 18 | Jack Willits | 7 | Son | — | California |
| 19 | Wayne Cox | 4 | Grandson | — | California |
| 20 | Robert A Willits | 3 | Grandson | — | California |
| 21 | Donna Frazier | 2 | Daughter | — | California |
| 22 | Charles F Olsen | 74 | Head | Minister | Denmark |
| 23 | Mary Smith Olsen | 64 | Wife | — | California |
| 24 | George W Davis | 55 | Head | Carpenter | California |
| 25 | Della Ida Davis | 36 | Wife | — | California |
| 26 | Evelyn S Brown | 14 | Stepdaughter | — | California |
| 27 | Eugene M Brown | 13 | Stepson | — | California |
| 28 | Paul Cerutti | 58 | Head | Farmer | Italy |
| 29 | Anna Cerutti | 48 | Wife | — | Italy |
| 30 | Joseph Stetson | 49 | Employee | Laborer | Washington |
| 31 | John M Sr Wilson | 45 | Head | Mechanic | Scotland |
| 32 | Jean H Wilson | 41 | Wife | — | Scotland |
| 33 | John M Jr Wilson | 17 | Son | — | California |
| 34 | Mary S Wilson | 13 | Daughter | — | California |
| 35 | Frank M Jr Goforth | 28 | Head | Farmer | California |
| 36 | Mary E Goforth | 22 | Wife | — | California |
| 37 | Stanley E Goforth | 2 | Son | — | California |
| 38 | Raymond M Brown | 78 | Head | — | California |
| 39 | Sarah M Brown | 79 | Wife | — | California |
| 40 | Evelyn S Brown | 55 | Daughter | — | 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)