MD
Mary Duncan — 1940 US Census Record
Model Tree available1940 United States Federal Census · Baltimore-City-County, Maryland
Our Model Tree links this Mary Duncan across the 1920, 1930 and 1940 US Censuses in Baltimore-City-County, Maryland (XGBoost, ~Confirmed), with identified parents James & Etta — first a daughter (b.~1915), then head of a 5-person household.
Age 25
b. ~1915
Female
Daughter
Born: Maryland
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Baltimore-City-County, Maryland |
| Surname | Duncan |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Baltimore City |
| 1935 Residence (County) | Baltimore City |
| Additional Details | |
| Occupation | Secretary |
| Industry | The College |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 230 |
| Highest Grade | Hs 4 |
| 1935 Residence | Same place |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
| Occupation | Secretary |
| Township / Ward | Baltimore City |
| Est. Birth Year | ~1915 |
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.
5 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Mary Duncan | Daughter | — | 25 | ~1915 |
| Lida Duncan | Daughter | — | 30 | ~1910 |
| William Duncan | Head | — | 58 | ~1882 |
| J Duncan | Son | — | 21 | ~1919 |
| Kate Duncan | Spouse | — | 58 | ~1882 |
Census Appearances
1920
Baltimore, Maryland
Daughter, age 5
Baltimore, Maryland · implied b. ~1915 — 8 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Duncan |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 5 |
| Marital Status | Single |
| Birthplace | Maryland |
| Father's Birthplace | Maryland |
| Mother's Birthplace | Maryland |
| Occupation | none |
| Speaks English | Yes |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
1930
Baltimore, Maryland
Daughter, age 15
Baltimore, Maryland · implied b. ~1915 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Duncan |
| Given Name | Mary E |
| Relationship to Head | daughter |
| Sex | F |
| Color / Race | White |
| Age | 15 |
| 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
Baltimore-City-County, Maryland
Daughter, age 25
Baltimore-City-County, Maryland · implied b. ~1915 — 5 household members
| Surname | Duncan |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Baltimore City |
| 1935 Residence (County) | Baltimore City |
| Occupation | Secretary |
| Industry | The College |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 230 |
| 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 Mary Duncan across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father James Duncan (~0.92 confidence) and mother Etta Duncan (~0.92 confidence) and mother Kate Duncan (~0.92 confidence) and father William Duncan (~0.92 confidence). The pedigree spans 1 generation with 4 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
James Duncan
b. ~1881
Source father
● Household
· direct · ~0.92
Mother
Etta Duncan
b. ~1882
Source mother
● Household
· direct · ~0.92
Mother
Kate Duncan
b. ~1882
Source mother
● Household
· direct · ~0.92
Father
William Duncan
b. ~1882
Source father
● Household
· direct · ~0.92
This person
Anchor record
Mary Duncan
Daughter · 1940 · age 25 · b. ~1915 · Maryland
★ You are viewing this record
Sibling
J Duncan
Sibling · 1940 · age 21
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Lida Duncan
Sibling · 1940 · age 30
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 — Baltimore-City-County, Maryland
Open full size
1940 US Federal Census — Baltimore-City-County, Maryland
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01531-00352)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Thomas A. Murphy | 53 | Head | Car Distributor | Maryland |
| 42 | Ella B. Murphy | 50 | Wife | — | Maryland |
| 43 | Rosemary Murphy | 25 | Daughter | — | Maryland |
| 44 | C. Carl Murphy | 24 | Son | Clerk | Maryland |
| 45 | J. Brady Murphy | 22 | Son | Clerk | Maryland |
| 46 | Elizabeth Voigt | 50 | Head | — | Maryland |
| 47 | Bertha Keyser | 52 | Lodger | Seamstress | Maryland |
| 48 | Elizabeth Malkmus | 38 | Lodger | — | Maryland |
| 49 | Walter H. Harvard | 60 | Head | — | Maryland |
| 50 | Blanch M. Harvard | 55 | Wife | — | Maryland |
| 51 | William H. Duncan | 58 | Head | — | Maryland |
| 52 | Kate R. Duncan | 58 | Wife | — | Maryland |
| 53 | Lida Duncan | 30 | Daughter | Teacher | Maryland |
| 54 | Mary Duncan THIS PERSON | 25 | Daughter | Secretary | Maryland |
| 55 | J. William Duncan | 21 | Son | Lab. Technician | Maryland |
| 56 | Margaret Blattau | 62 | Head | — | Maryland |
| 57 | Frederick Wagner | 46 | Head | Plumber | Maryland |
| 58 | Clara Wagner | 45 | Wife | — | Maryland |
| 59 | Carl Wagner | 21 | Son | New Worker | Maryland |
| 60 | Gordon Wagner | 19 | Son | Assembler | Maryland |
| 61 | Selma Wagner | 17 | Daughter | — | Maryland |
| 62 | Hetty Wagner | 6 | Daughter | — | Maryland |
| 63 | Clara Duffy | 60 | Head | Nurse | West Virginia |
| 64 | Margaret Duffy | 72 | Sister | — | West Virginia |
| 65 | Charles Duffy | 50 | Brother | Repairman | West Virginia |
| 66 | Mary Garvy | 74 | Sister | — | West Virginia |
| 67 | Louise Jones | 60 | Head | — | Maryland |
| 68 | Robert Harris | 10 | Adopted son | — | Maryland |
| 69 | Frank J. Tuckson | 39 | Head | — | Virginia |
| 70 | Rose S. Tuckson | 29 | Wife | — | Maryland |
| 71 | Robert H. Tuckson | 5 | Son | Cook | Maryland |
| 72 | Nettie Simms | 33 | Head | — | Maryland |
| 73 | John Simms | 15 | Son | — | Maryland |
| 74 | James Simms | 14 | Son | — | Maryland |
| 75 | Alice Simms | 12 | Daughter | — | Maryland |
| 76 | Mary Simms | 10 | Daughter | — | Maryland |
| 77 | Grace Simms | 9 | Daughter | — | Maryland |
| 78 | Robert Simms | 6 | Son | — | Maryland |
| 79 | Joseph Simms | 4 | Son | — | Maryland |
| 80 | Willie Coleman | 30 | Head | Laborer | N. Carolina |
Pedigree Summary
Mary + 2 siblings
Gen 1 · 4 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)