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Mary Olsen — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Lake-County, Illinois
Our Model Tree links this Mary Olsen across the 1930 and 1940 US Censuses in Lake-County, Illinois (XGBoost, ~Confirmed) — first a spouse (b.~1890), then head of a 9-person household.
Age 50
b. ~1890
Female
Spouse
Born: Wisconsin
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Lake-County, Illinois |
| Surname | Olsen |
| Given Name | Mary M. |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 50 |
| Marital Status | Married |
| Birthplace | Wisconsin |
| 1935 Residence (City) | Waukegan City |
| Additional Details | |
| Industry | 0 |
| Class of Worker | 0 |
| Highest Grade | H 4 |
| 1935 Residence | Same Place |
| Birth State | Wisconsin |
| Birth Country | United States |
| Birthplace (normalized) | wisconsin |
| Township / Ward | Waukegan City |
| Est. Birth Year | ~1890 |
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.
9 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Frank Olsen | Son | — | 16 | ~1924 |
| Hugh Olsen | Son | — | 18 | ~1922 |
| Robert Olsen | Son | — | 23 | ~1917 |
| Nels Olsen | Head | — | 56 | ~1884 |
| Helen Olsen | Daughter | — | 25 | ~1915 |
| Mary Olsen | Spouse | — | 50 | ~1890 |
| Edward Olsen | Son | — | 22 | ~1918 |
| Thomas Olsen | Son | — | 21 | ~1919 |
| Alice Olsen | Daughter | — | 9 | ~1931 |
Census Appearances
1930
Lake, Illinois
Other, age 39
Lake, Illinois · implied b. ~1891 — 8 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Olsen |
| Given Name | Mary M. |
| Relationship to Head | Wife-H |
| Sex | F |
| Color / Race | White |
| Age | 39 |
| Marital Status | Married |
| Birthplace | Wisconsin |
| Age at First Marriage | 22 |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Wisconsin |
| Can Read/Write | Yes |
| Birth State | Wisconsin |
| Birth Country | United States |
| Birthplace (normalized) | wisconsin |
1940
Lake-County, Illinois
Spouse, age 50
Lake-County, Illinois · implied b. ~1890 — 9 household members
| Surname | Olsen |
| Given Name | Mary M. |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 50 |
| Marital Status | Married |
| Birthplace | Wisconsin |
| 1935 Residence (City) | Waukegan City |
| Industry | 0 |
| Class of Worker | 0 |
| Highest Grade | H 4 |
| 1935 Residence | Same Place |
| Birth State | Wisconsin |
| Birth Country | United States |
| Birthplace (normalized) | wisconsin |
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 Olsen across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Olsen
Spouse · 1940 · age 50 · b. ~1890 · 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 — Lake-County, Illinois
Open full size
1940 US Federal Census — Lake-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00831-00361)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Dora | 43 | Lodger | Teacher | England |
| 2 | Emmanuel Moberg | 66 | Head | — | Sweden |
| 3 | Emma C. Moberg | 62 | Wife | — | Sweden |
| 4 | Alfred Moberg | 52 | Brother | Machinist | Sweden |
| 5 | Nels P. Olsen | 56 | Head | Assistant Engineer | Wisconsin |
| 6 | Mary M. Olsen THIS PERSON | 50 | Wife | — | Wisconsin |
| 7 | Helen L. Olsen | 25 | Daughter | Registered Nurse | Illinois |
| 8 | Robert M. Olsen | 23 | Son | Production Tracer | Illinois |
| 9 | Edward L. Olsen | 22 | Son | — | Illinois |
| 10 | Thomas M. Olsen | 21 | Son | Machinist | Illinois |
| 11 | Hugh H. Olsen | 18 | Son | — | Illinois |
| 12 | Frank J. Olsen | 16 | Son | — | Illinois |
| 13 | Alice M. Olsen | 9 | Daughter | — | Illinois |
| 14 | John J. Russell | 36 | Head | Boiler Maintenance | Wisconsin |
| 15 | Mary R. Russell | 38 | Wife | — | Wisconsin |
| 16 | Marie S. Russell | 8 | Daughter | — | Illinois |
| 17 | John P. Russell | 1 | Son | — | Illinois |
| 18 | Matilda S. Johnson | 85 | Head | — | Sweden |
| 19 | Albert A. Johnson | 45 | Nephew | Proprietor | Sweden |
| 20 | John B. Johnson | 37 | Nephew | Laborer | Sweden |
| 21 | Wilhelmina Johnson | 81 | Head | — | Sweden |
| 22 | Anton F. Johnson | 54 | Son | Teacher | Illinois |
| 23 | Olga M. Fosberg | 51 | Daughter | Electrologist | Illinois |
| 24 | John S. Fosberg | 20 | Son | Salesman | Illinois |
| 25 | Donald S. Thomas | 69 | Head | Employment Agent | Canada |
| 26 | Lillian T. Thomas | 69 | Wife | Librarian | England |
| 27 | Vivian M. Thomas | 46 | Daughter | Librarian | Illinois |
| 28 | Herbert J. Mellin | 53 | Head | Schedule Clerk | Wisconsin |
| 29 | Mable M. Mellin | 53 | Wife | — | Illinois |
| 30 | Donald C. Mellin | 25 | Son | Interne Medical Student | Illinois |
| 31 | Ruth Ruston | 24 | Lodger | Teacher | Illinois |
| 32 | Matilda Malmstrom | 66 | Head | — | Sweden |
| 33 | Albert E. Nordstrom | 37 | Head | Proprietor | Illinois |
| 34 | Esther C. Nordstrom | 37 | Wife | Saleswoman | Wisconsin |
| 35 | Victor O. Matson | 27 | Head | Sign Painter | Illinois |
| 36 | Eleanor J. Matson | 26 | Wife | — | Illinois |
| 37 | Judith E. Matson | 5 | Daughter | — | Illinois |
| 38 | Ronald S. Matson | 1 | Son | — | Illinois |
| 39 | William H. Peck | 27 | Head | Molder | Michigan |
| 40 | Nelle J. Peck | 26 | Wife | — | Minnesota |
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)