MJ
Mary Jensen — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Boone-County, Illinois
Our Model Tree links this Mary Jensen across the 1920, 1930 and 1940 US Censuses in Boone-County, Illinois (XGBoost, ~Confirmed) — first a spouse (b.~1884), then head of a 5-person household.
Age 56
b. ~1884
Female
Spouse
Born: Bohemia
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Boone-County, Illinois |
| Surname | Jensen |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 56 |
| Marital Status | Married |
| Birthplace | Bohemia |
| 1935 Residence (City) | Belvidere city |
| 1935 Residence (County) | Boone |
| Naturalization Status | Naturalized |
| Additional Details | |
| Income (1939) | 0 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth Country | Czechoslovakia |
| Birthplace (normalized) | bohemia |
| Township / Ward | Belvidere City |
| Est. Birth Year | ~1884 |
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 |
|---|---|---|---|---|
| Torwald Jensen | Head | — | 66 | ~1874 |
| George Jensen | Son | — | 23 | ~1917 |
| Carl Jensen | Son | — | 26 | ~1914 |
| John Jensen | Son | — | 37 | ~1903 |
| Mary Jensen | Spouse | — | 56 | ~1884 |
Census Appearances
1920
Boone, Illinois
Spouse, age 35
Boone, Illinois · implied b. ~1885 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Jenson |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 35 |
| Marital Status | Married |
| Birthplace | Bohemia |
| Naturalization Status | Naturalized |
| Father's Birthplace | Bohemia |
| Mother's Birthplace | Bohemia |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Mother Tongue | Bohemian |
| Birth Country | Czechoslovakia |
| Birthplace (normalized) | bohemia |
1930
Boone, Illinois
Other, age 46
Boone, Illinois · implied b. ~1884 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Jensen |
| Given Name | Mary |
| Relationship to Head | Wife-H |
| Sex | F |
| Color / Race | White |
| Age | 46 |
| Marital Status | Married |
| Birthplace | Bohemia |
| Year of Immigration | 1915 |
| Age at First Marriage | 18 |
| Father's Birthplace | Bohemia |
| Mother's Birthplace | Bohemia |
| Can Read/Write | Yes |
| Mother Tongue | Bohemian |
| Birth Country | Czechoslovakia |
| Birthplace (normalized) | bohemia |
1940
Boone-County, Illinois
Spouse, age 56
Boone-County, Illinois · implied b. ~1884 — 5 household members
| Surname | Jensen |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 56 |
| Marital Status | Married |
| Birthplace | Bohemia |
| 1935 Residence (City) | Belvidere city |
| 1935 Residence (County) | Boone |
| Naturalization Status | Naturalized |
| Income (1939) | 0 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth Country | Czechoslovakia |
| Birthplace (normalized) | bohemia |
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 Jensen across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage.
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This person
Anchor record
Mary Jensen
Spouse · 1940 · age 56 · b. ~1884 · Illinois
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Confirmed / household (~0.90+)
Probable / derived (~0.65–0.89)
Candidate (<0.65, unverified)
Original Census Page
1940 US Federal Census — Boone-County, Illinois
Open full size
1940 US Federal Census — Boone-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00760-00100)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Alma Gray | 57 | Wife | — | Illinois |
| 2 | Iva A. Hammond | 56 | Head | Underwriter | Illinois |
| 3 | Olive Hammond | 59 | Sister | — | Illinois |
| 4 | Edith A. Hammond | 41 | Sister | Bank Ledger Stenographer | Illinois |
| 5 | Lena Ellingson | 78 | Head | — | Illinois |
| 6 | Oscar Jordan | 52 | Head | Stationary Engineer | Illinois |
| 7 | Greta Jordan | 53 | Wife | — | Germany |
| 8 | Lorraine Jordan | 20 | Daughter | Sprayer | Illinois |
| 9 | Howard Jordan | 18 | Son | — | Illinois |
| 10 | Eric Lind | 37 | Head | Coremaker | Sweden |
| 11 | Dorothy Lind | 34 | Wife | — | Illinois |
| 12 | Joanne Lind | 7 | Daughter | — | Illinois |
| 13 | Jeanne Lind | 7 | Daughter | — | Illinois |
| 14 | Edith Long | 67 | Head | — | Wisconsin |
| 15 | Robert Baker | 63 | Head | Boiler Fireman | Missouri |
| 16 | Mary Baker | 54 | Wife | Baker Helper | Missouri |
| 17 | Torwald Jensen | 66 | Head | Night Watchman | Denmark |
| 18 | Mary Jensen THIS PERSON | 56 | Wife | — | Bohemia |
| 19 | John Jensen | 37 | Son | — | Illinois |
| 20 | Carl Jensen | 26 | Son | Moulder | Illinois |
| 21 | George Jensen | 23 | Son | Music Teacher | Illinois |
| 22 | William Campbell | 47 | Head | Assembler | Scotland |
| 23 | Emily Campbell | 42 | Wife | — | North Ireland |
| 24 | Mary Seiler | 80 | Head | — | Germany |
| 25 | William Seiler | 50 | Son | Moulder | Illinois |
| 26 | Clyde Brown | 53 | Head | Garage Mechanic | Illinois |
| 27 | Esther Brown | 48 | Wife | — | Illinois |
| 28 | Bernice Brown | 14 | Daughter | — | Illinois |
| 29 | Esther Brown | 13 | Daughter | — | Illinois |
| 30 | Audrey Brown | 10 | Daughter | — | Illinois |
| 31 | John Brown | 9 | Son | — | Illinois |
| 32 | George Bleakley | 38 | Head | Repairman | Illinois |
| 33 | Theresa Bleakley | 33 | Wife | Sub. Operator | Illinois |
| 34 | Eugene Bleakley | 11 | Son | — | Illinois |
| 35 | Gerald Bleakley | 9 | Son | — | Illinois |
| 36 | Margaret Bleakley | 73 | Mother | — | England |
| 37 | Claude E. Oakley | 58 | Head | Property Repair | Illinois |
| 38 | Olive Oakley | 49 | Wife | — | Illinois |
| 39 | Laverne Oakley | 22 | Son | Wood Worker | Illinois |
| 40 | Maynard Oakley | 18 | Son | — | 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)