MK
Mary Koch — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Mary Koch across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a head (b.~1876), then head of a 2-person household.
Age 64
b. ~1876
Female
Head
Born: Germany
Widowed
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Koch |
| Given Name | Mary |
| Relationship to Head | Head |
| Sex | F |
| Color / Race | White |
| Age | 64 |
| Marital Status | Widowed |
| Birthplace | Germany |
| 1935 Residence (City) | La Grange Village |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Additional Details | |
| Highest Grade | 8 |
| 1935 Residence | Same place |
| Birth Country | Germany |
| Birthplace (normalized) | germany |
| Township / Ward | La Grange Village |
| Est. Birth Year | ~1876 |
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.
2 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Louisa Koch | Daughter | — | 16 | ~1924 |
| Mary Koch | Head | — | 64 | ~1876 |
Census Appearances
1920
Cook, Illinois
Spouse, age 45
Cook, Illinois · implied b. ~1875 — 2 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Koch |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 45 |
| Marital Status | Married |
| Birthplace | Germany |
| Father's Birthplace | Germany |
| Mother's Birthplace | Germany |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Mother Tongue | German |
| Birth Country | Germany |
| Birthplace (normalized) | germany |
1930
Cook, Illinois
Spouse, age 54
Cook, Illinois · implied b. ~1876 — 4 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Koch |
| Given Name | Marie |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 54 |
| Marital Status | Married |
| Birthplace | Germany |
| Naturalization Status | Naturalized |
| Year of Immigration | 1878 |
| Age at First Marriage | 21 |
| Father's Birthplace | Germany |
| Mother's Birthplace | Germany |
| Occupation | none |
| Can Read/Write | Yes |
| Mother Tongue | German |
| Birth Country | Germany |
| Birthplace (normalized) | germany |
1940
Cook-County, Illinois
Head, age 64
Cook-County, Illinois · implied b. ~1876 — 2 household members
| Surname | Koch |
| Given Name | Mary |
| Relationship to Head | Head |
| Sex | F |
| Color / Race | White |
| Age | 64 |
| Marital Status | Widowed |
| Birthplace | Germany |
| 1935 Residence (City) | La Grange Village |
| 1935 Residence (County) | Cook |
| Naturalization Status | Naturalized |
| Highest Grade | 8 |
| 1935 Residence | Same place |
| Birth Country | Germany |
| Birthplace (normalized) | germany |
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 Koch 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 Koch
Head · 1940 · age 64 · b. ~1876 · Illinois
★ You are viewing this record
Confirmed / household (~0.90+)
Probable / derived (~0.65–0.89)
Candidate (<0.65, unverified)
Original Census Page
1940 US Federal Census — Cook-County, Illinois
Open full size
1940 US Federal Census — Cook-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00782-00218)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Lou Yeater | 24 | Son | Case Worker | Illinois |
| 2 | Gertrude Yeater | 24 | Daughter-in-law | Telephone Operator | Illinois |
| 3 | Clifford Rayapas | 23 | Boarder | Tool Maker | Illinois |
| 4 | B. Nelson Mcmechen | 27 | Head | Supply Man | Illinois |
| 5 | Twila Mcmechen | 26 | Wife | — | Illinois |
| 6 | Janet Mcmechen | 1 | Daughter | — | Illinois |
| 7 | Mary Koch THIS PERSON | 64 | Head | — | Germany |
| 8 | Louisa Koch | 16 | Daughter | — | Illinois |
| 9 | Maurice Nelson | 40 | Head | Welding Supervisor | Nebraska |
| 10 | Janette Nelson | 38 | Wife | — | Wyoming |
| 11 | Rosalie Rust | 20 | Niece | Secretary | Nebraska |
| 12 | Anthony Nelson | 65 | Father | Wine-Chief | Kansas |
| 13 | Charles Wotke | 55 | Head | Meat Cutter | Illinois |
| 14 | Fannie Wotke | 44 | Wife | — | Illinois |
| 15 | Robert Hamilton | 18 | Brother-in-law | — | Illinois |
| 16 | Harold Oakes | 48 | Head | Chief Of Police | Illinois |
| 17 | Ethel A. Oakes | 44 | Wife | — | Illinois |
| 18 | Betty Jane Oakes | 19 | Daughter | Beautician | Illinois |
| 19 | Maurice Creighton | 46 | Head | Life Insurance Agent | Illinois |
| 20 | Lucille Creighton | 37 | Wife | — | Illinois |
| 21 | Rosemary Creighton | 15 | Daughter | — | Illinois |
| 22 | Virginia Ann Creighton | 11 | Daughter | — | Illinois |
| 23 | Betty Lou Creighton | 10 | Daughter | — | Illinois |
| 24 | Louise Radell | 82 | Head | — | Wisconsin |
| 25 | James E. Gorsky | 29 | Head | Life Insurance Agent | Illinois |
| 26 | Beatrice Gorsky | 27 | Wife | Secretary | Illinois |
| 27 | Alice L. Culbertson | 81 | Head | — | Ohio |
| 28 | Henry Jacobi | 60 | Son-in-law | Manager | Ohio |
| 29 | Bessie C. Jacobi | 57 | Daughter | — | Ohio |
| 30 | L. Thomas Paradis | 63 | Head | Attorney At Law | Illinois |
| 31 | Johanne Paradis | 54 | Wife | — | Illinois |
| 32 | Thomas Jr. Paradis | 25 | Son | Merchandising | Illinois |
| 33 | Maude Paradis | 25 | Daughter | Comptometer Operator | Illinois |
| 34 | Hazel White | 18 | Maid | Maid | Illinois |
| 35 | V. O. Winkenweder | 46 | Head | Manufacturer Representative | Indiana |
| 36 | Elsa Winkenweder | 47 | Wife | — | Indiana |
| 37 | Florence Winkenweder | 12 | Son | — | Illinois |
| 38 | Walter W. Ragu | 38 | Head | Electrical Engineer | Kansas |
| 39 | Joy Ragu | 32 | Wife | — | Illinois |
| 40 | Ruth Elaine Ragu | 1 | 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)