MJ
Mary Jennings — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Dupage-County, Illinois
Our Model Tree links this Mary Jennings across the 1930 and 1940 US Censuses in Dupage-County, Illinois (XGBoost, ~Confirmed) — first a daughter (b.~1927), then head of a 10-person household.
Age 13
b. ~1927
Female
Daughter
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Dupage-County, Illinois |
| Surname | Jennings |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 13 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Downers Grove |
| 1935 Residence (County) | Du Page |
| Additional Details | |
| Highest Grade | H 6 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Township / Ward | Downers Grove |
| Est. Birth Year | ~1927 |
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.
10 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Barbara Jennings | Daughter | — | 12 | ~1928 |
| Winifred Jennings | Daughter | — | 17 | ~1923 |
| Dorothy Jennings | Daughter | — | 10 | ~1930 |
| Therese Jennings | Daughter | — | 9 | ~1931 |
| Mary Jennings | Daughter | — | 13 | ~1927 |
| Walter Jennings | Head | — | 45 | ~1895 |
| Walter Jennings | Son | — | 11 | ~1929 |
| Jerome Jennings | Son | — | 3 | ~1937 |
| James Jennings | Son | — | 15 | ~1925 |
| Clara Jennings | Spouse | — | 44 | ~1896 |
Census Appearances
1930
Cook, Illinois
Daughter, age 2
Cook, Illinois · implied b. ~1928 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Jennings |
| Given Name | Margaret M |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 2 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Dupage-County, Illinois
Daughter, age 13
Dupage-County, Illinois · implied b. ~1927 — 10 household members
| Surname | Jennings |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 13 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Downers Grove |
| 1935 Residence (County) | Du Page |
| Highest Grade | H 6 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
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 Jennings across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Jennings
Daughter · 1940 · age 13 · b. ~1927 · Illinois
★ You are viewing this record
Sibling
Winifred Jennings
Sibling · 1940 · age 17
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Therese Jennings
Sibling · 1940 · age 9
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Barbara Jennings
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Jennings
Sibling · 1940 · age 15
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Dorothy Jennings
Sibling · 1940 · age 10
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Walter Jennings
Sibling · 1940 · age 11
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Jerome Jennings
Sibling · 1940 · age 3
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 — Dupage-County, Illinois
Open full size
1940 US Federal Census — Dupage-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00797-00578)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Sylvester Smith | 40 | Head | Laborer | Missouri |
| 2 | Ada O Smith | 34 | Wife | — | Minnesota |
| 3 | Sylvester Smith | 17 | Son | — | Minnesota |
| 4 | Donald Smith | 16 | Son | — | Minnesota |
| 5 | Marcella Smith | 14 | Daughter | — | Minnesota |
| 6 | Beverly Smith | 12 | Daughter | — | Minnesota |
| 7 | Gene S Smith | 11 | Son | — | Minnesota |
| 8 | Nancy Smith | 8 | Daughter | — | Illinois |
| 9 | Ada Marie Smith | 6 | Daughter | — | Illinois |
| 10 | Lolita Smith | 4 | Daughter | — | Illinois |
| 11 | Patricia Smith | 2 | Daughter | — | Illinois |
| 12 | Frederick Caldwell | 44 | Head | — | Nebraska |
| 13 | Evelyn Caldwell | 43 | Wife | — | Illinois |
| 14 | William F Caldwell | 71 | Father | Minister | Nebraska |
| 15 | Alice Caldwell | 72 | Mother | — | Illinois |
| 16 | Zella Caldwell | 33 | Sister | — | Oregon |
| 17 | Walter Jennings | 45 | Head | Fireman | Illinois |
| 18 | Clara O Jennings | 44 | Wife | — | Illinois |
| 19 | Winifred Jennings | 17 | Daughter | — | Illinois |
| 20 | James Jennings | 15 | Son | — | Illinois |
| 21 | Mary Jennings THIS PERSON | 13 | Daughter | — | Illinois |
| 22 | Walter Jennings | 11 | Son | — | Illinois |
| 23 | Dorothy Jennings | 10 | Daughter | — | Illinois |
| 24 | Barbara Jennings | 12 | Daughter | — | Illinois |
| 25 | Therese Jennings | 9 | Daughter | — | Illinois |
| 26 | Jerome Jennings | 3 | Son | — | Illinois |
| 27 | Gilbert Lacy | 53 | Head | At Home | Illinois |
| 28 | Ruth Lacy | 45 | Wife | — | Illinois |
| 29 | Frank C Lacy | 81 | Father | — | Illinois |
| 30 | Grant C Rickards | 27 | Head | Special Agent | Illinois |
| 31 | Jane Rickards | 27 | Wife | Editor | Illinois |
| 32 | Judith Rickards | 4 | Daughter | — | Illinois |
| 33 | Herbert Woodward | 33 | Lodger | Service Station Attendant | Illinois |
| 34 | Robert Bucklin | 33 | Head | Tailor | Ohio |
| 35 | Pauline Bucklin | 25 | Wife | — | Ohio |
| 36 | Fred Montgomery | 42 | Head | Tool & Die Maker | Missouri |
| 37 | Carrie Montgomery | 42 | Wife | — | Missouri |
| 38 | John Montgomery | 20 | Son | General Work | Illinois |
| 39 | Kenneth Montgomery | 18 | Son | — | Illinois |
| 40 | Jeanette Montgomery | 16 | Daughter | — | Illinois |
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)