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John Campbell — 1940 US Census Record
Model Tree available1940 United States Federal Census · Carroll-County, Maryland
Our Model Tree links this John Campbell across the 1920, 1930 and 1940 US Censuses in Carroll-County, Maryland (XGBoost, ~Confirmed), with identified parents Marshall & Marshall — first a son (b.~1910), then head of a 4-person household.
Age 30
b. ~1910
Male
Son
Born: Maryland
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Carroll-County, Maryland |
| Surname | Campbell |
| Given Name | John W. |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 30 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Westminster |
| 1935 Residence (County) | Carroll |
| Additional Details | |
| Occupation | farmer |
| Industry | general farm |
| Class of Worker | OA |
| Hours Worked | 4 |
| Income (1939) | 0 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
| Occupation | Farmer |
| Township / Ward | Westminster |
| Est. Birth Year | ~1910 |
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.
4 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Marshall Campbell | Head | — | 59 | ~1881 |
| H Campbell | Son | — | 27 | ~1913 |
| John Campbell | Son | — | 30 | ~1910 |
| Mary Campbell | Spouse | — | 52 | ~1888 |
Census Appearances
1920
Carroll, Maryland
Son, age 9
Carroll, Maryland · implied b. ~1911 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Campbell |
| Given Name | John W |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 9 |
| Marital Status | Single |
| Birthplace | Maryland |
| Father's Birthplace | Maryland |
| Mother's Birthplace | Maryland |
| Occupation | none |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
1930
Carroll, Maryland
Son, age 20
Carroll, Maryland · implied b. ~1910 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Campbell |
| Given Name | John M. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 20 |
| Marital Status | Single |
| Birthplace | Maryland |
| Father's Birthplace | Maryland |
| Mother's Birthplace | Maryland |
| Occupation | none |
| Can Read/Write | Yes |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
1940
Carroll-County, Maryland
Son, age 30
Carroll-County, Maryland · implied b. ~1910 — 4 household members
| Surname | Campbell |
| Given Name | John W. |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 30 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Westminster |
| 1935 Residence (County) | Carroll |
| Occupation | farmer |
| Industry | general farm |
| Class of Worker | OA |
| Hours Worked | 4 |
| Income (1939) | 0 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
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 John Campbell across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father Marshall Campbell (~0.92 confidence) and father Marshall Campbell (~0.92 confidence) and father Marshall Campbell (~0.92 confidence) and mother Mary Campbell (~0.92 confidence) and mother Mary Campbell (~0.92 confidence). The pedigree spans 1 generation with 5 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
Marshall Campbell
b. ~1885
Source father
● Household
· direct · ~0.92
Father
Marshall Campbell
b. ~1881
Source father
● Household
· direct · ~0.92
Father
Marshall Campbell
b. ~1882
Source father
● Household
· direct · ~0.92
Mother
Mary Campbell
b. ~1888
Source mother
● Household
· direct · ~0.92
Mother
Mary Campbell
b. ~1888
Source mother
● Household
· direct · ~0.92
This person
Anchor record
John Campbell
Son · 1940 · age 30 · b. ~1910 · Maryland
★ You are viewing this record
Sibling
H Campbell
Sibling · 1940 · age 27
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 — Carroll-County, Maryland
Open full size
1940 US Federal Census — Carroll-County, Maryland
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01544-00550)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Jeanne Elvira Miller | 11 | daughter | — | Maryland |
| 2 | Extra Line Extra Line | None | Extra Line | Extra Line | Extra Line |
| 3 | John H. Palty | 40 | Head | Truck Driver | Maryland |
| 4 | Alicia M. Palty | 35 | wife | Sewing | Maryland |
| 5 | Roland S. Farrow | 45 | Head | Painter | Maryland |
| 6 | Helen J. Farrow | 39 | wife | Machine Operator | Maryland |
| 7 | Anna J. Farrow | 10 | daughter | — | Maryland |
| 8 | Robert S. Farrow | 1 | son | — | Pennsylvania |
| 9 | Edward B. Arnsdorff | 60 | Lodger | Truck Driver | Maryland |
| 10 | Stanley L. Sleight | 33 | Head | Trimmer | Maryland |
| 11 | Helen C. Sleight | 30 | wife | Stitcher | Pennsylvania |
| 12 | Mary M. Sleight | 11 | daughter | — | Maryland |
| 13 | Margaret F. Sleight | 1 | son | — | Pennsylvania |
| 14 | Here Ends Block Here Ends Block | None | Here ends Block | Here Ends Block | Here ends Block |
| 15 | Marshall E. Campbell | 59 | Head | Farmer | Maryland |
| 16 | Mary E. Campbell | 52 | wife | — | Maryland |
| 17 | John W. Campbell THIS PERSON | 30 | son | Farmer | Maryland |
| 18 | H. Wilson Campbell | 27 | son | General Clerk | Maryland |
| 19 | Frank W. Mathey | 56 | Head | Merchant | Maryland |
| 20 | Stella J. Mathey | 51 | wife | — | Michigan |
| 21 | Mary E. Mathey | 25 | daughter | Home Economics Teacher | Maryland |
| 22 | Jane B. Mathey | 23 | daughter | — | Maryland |
| 23 | Frank W. Jr. Mathey | 20 | son | — | Maryland |
| 24 | Margaret Mathey | 13 | daughter | — | Maryland |
| 25 | Grace E. Knopp | 46 | Sister-in-law | Nurse | Michigan |
| 26 | Lena Patterson | 38 | maid | Maid | Maryland |
| 27 | George S. Willes | 74 | Head | English Teacher | North Carolina |
| 28 | Merillat C. Willes | 66 | wife | — | Virginia |
| 29 | Claude S. Kimmey | 61 | Head | Manager | Maryland |
| 30 | Anna M. Kimmey | 56 | wife | — | Maryland |
| 31 | Eleanor M. Kimmey | 36 | daughter | Music Teacher | Maryland |
| 32 | Ruth S. Kimmey | 20 | daughter | — | Maryland |
| 33 | Mary J. Kimmey | 15 | daughter | — | Maryland |
| 34 | L. Bradley Cottman | 26 | Head | Salesman | New York |
| 35 | Edith F. Cottman | 26 | wife | — | Massachusetts |
| 36 | Cornelius Cottman | 3 | son | 0 | Maryland |
| 37 | Mary L. Cottman | 0 | daughter | 0 | Maryland |
| 38 | Extra Line Extra Line | None | Extra Line | Extra Line | Extra Line |
| 39 | George H. Rutan | 37 | Head | President & Manager | Delaware |
| 40 | Madeline F. Rutan | 26 | wife | — | North Carolina |
Pedigree Summary
John + 1 sibling
Gen 1 · 5 parents
~0.92
Max depth 4 (1900–1950 window)
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)