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John Koch — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Scott-County, Iowa
Our Model Tree links this John Koch across the 1920, 1930 and 1940 US Censuses in Scott-County, Iowa (XGBoost, ~Confirmed) — first a head (b.~1862), then head of a 3-person household.
Age 78
b. ~1862
Male
Head
Born: Iowa
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Scott-County, Iowa |
| Surname | Koch |
| Given Name | John |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 78 |
| Marital Status | Married |
| Birthplace | Iowa |
| 1935 Residence (City) | Davenport City |
| 1935 Residence (County) | Scott |
| Additional Details | |
| Class of Worker | 0 |
| Hours Worked | 0 |
| Highest Grade | No 8 |
| 1935 Residence | Same place |
| Birth State | Iowa |
| Birth Country | United States |
| Birthplace (normalized) | iowa |
| Township / Ward | Davenport City |
| Est. Birth Year | ~1862 |
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.
3 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| John Koch | Head | — | 78 | ~1862 |
| Anna Koch | Spouse | — | 74 | ~1866 |
| Hilda Koch | Daughter | — | 51 | ~1889 |
Census Appearances
1920
Scott, Iowa
Head, age 58
Scott, Iowa · implied b. ~1862 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Koch |
| Given Name | John |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 58 |
| Marital Status | Married |
| Birthplace | Iowa |
| Father's Birthplace | Germany |
| Mother's Birthplace | Germany |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Home Owned/Rented | R |
| Birth State | Iowa |
| Birth Country | United States |
| Birthplace (normalized) | iowa |
1930
Scott, Iowa
Head, age 68
Scott, Iowa · implied b. ~1862 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Koch |
| Given Name | John |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 68 |
| Marital Status | Married |
| Birthplace | Iowa |
| Age at First Marriage | 26 |
| Father's Birthplace | Germany |
| Mother's Birthplace | Germany |
| Can Read/Write | Yes |
| Home Owned/Rented | O |
| Home Value / Rent | 4000 |
| Radio Set | R |
| Veteran | No |
| Birth State | Iowa |
| Birth Country | United States |
| Birthplace (normalized) | iowa |
1940
Scott-County, Iowa
Head, age 78
Scott-County, Iowa · implied b. ~1862 — 3 household members
| Surname | Koch |
| Given Name | John |
| Relationship to Head | Head |
| Sex | M |
| Color / Race | White |
| Age | 78 |
| Marital Status | Married |
| Birthplace | Iowa |
| 1935 Residence (City) | Davenport City |
| 1935 Residence (County) | Scott |
| Class of Worker | 0 |
| Hours Worked | 0 |
| Highest Grade | No 8 |
| 1935 Residence | Same place |
| Birth State | Iowa |
| Birth Country | United States |
| Birthplace (normalized) | iowa |
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 John 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
John Koch
Head · 1940 · age 78 · b. ~1862 · Iowa
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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 — Scott-County, Iowa
Open full size
1940 US Federal Census — Scott-County, Iowa
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01203-00760)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Adell B. Mccarthy | 36 | Wife | — | Iowa |
| 42 | Joseph Mccarthy | 10 | Son | — | Iowa |
| 43 | Patricia Mccarthy | 7 | Daughter | — | Iowa |
| 44 | Mary Mccarthy | 4 | Daughter | — | Iowa |
| 45 | Della Stanley | 49 | Housekeeper | Maid | Iowa |
| 46 | Laura Vander Slice | 72 | Head | — | Illinois |
| 47 | Harriett Liddell | 60 | Head | — | Iowa |
| 48 | Arthur Piper | 57 | Head | Mail Clerk | Illinois |
| 49 | Beaulah Piper | 50 | Wife | — | Iowa |
| 50 | Paul E. Conway | 40 | Head | Reporter | Iowa |
| 51 | Lola M. Conway | 39 | Wife | — | Wisconsin |
| 52 | Patrick Conway | 4 | Son | — | Iowa |
| 53 | James W. Conway | 26 | Brother | Collector | Iowa |
| 54 | Claude Duley | 45 | Head | Proprietor | Ohio |
| 55 | Esther Duley | 42 | Wife | — | Iowa |
| 56 | Jerry Duley | 12 | Son | — | Iowa |
| 57 | Richard Duley | 10 | Son | — | Iowa |
| 58 | Carylann Duley | 5 | Daughter | — | Iowa |
| 59 | Stanley Corrett | 57 | Head | Salesman | England |
| 60 | Estelle Corrett | 60 | Wife | — | Wisconsin |
| 61 | Ruth Corrett | 23 | Daughter | Stenographer | Minnesota |
| 62 | Thomas Corrett | 20 | Son | Bookkeeper | Minnesota |
| 63 | John Koch THIS PERSON | 78 | Head | — | Iowa |
| 64 | Anna Koch | 74 | Wife | — | Iowa |
| 65 | Hilda Koch | 51 | Daughter | — | Iowa |
| 66 | Walter Lambach | 43 | Head | Salesman | Iowa |
| 67 | Frieda Lambach | 42 | Wife | — | Iowa |
| 68 | Donna M. Lambach | 3 | Daughter | — | Iowa |
| 69 | Mollie Schaly | 63 | Mother | — | Germany |
| 70 | Marion Mcroberts | 19 | Niece | Clerk | Iowa |
| 71 | Arthur E. Larson | 56 | Head | Salesman | Iowa |
| 72 | Hattie J. Larson | 56 | Wife | — | Iowa |
| 73 | Elizabeth F. Larson | 20 | Daughter | Manager | Iowa |
| 74 | Elmer Lack | 39 | Head | Owner | Iowa |
| 75 | Annie Lack | 40 | Wife | — | Sweden |
| 76 | Ruskin Lack | 16 | Son | — | Iowa |
| 77 | Barbara Lack | 11 | Daughter | — | Iowa |
| 78 | Jimmy Lack | 9 | Son | — | Iowa |
| 79 | Herbert R. Tomson | 44 | Head | Advertising Manager | Iowa |
| 80 | Mildred Tomson | 42 | Wife | — | Iowa |
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)