John Koch — 1940 US Census Record

Linked across censuses

1940 United States Federal Census · Cook-County, Illinois

Our Model Tree links this John Koch across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a head (b.~1885), then head of a 3-person household.

Age 55 b. ~1885 Male Head Born: Wisconsin Married

1940 Census Record Details

Census Year	1940
Location	Cook-County, Illinois
Surname	Koch
Given Name	John
Relationship to Head	Head
Sex	M
Color / Race	White
Age	55
Marital Status	Married
Birthplace	Wisconsin
1935 Residence (City)	Chicago City
1935 Residence (County)	Cook
Additional Details
Occupation	Machinist
Industry	Surface Lines
Class of Worker	PW
Hours Worked	40
Income (1939)	2080
Highest Grade	H 4
1935 Residence	Same place
Birth State	Wisconsin
Birth Country	United States
Birthplace (normalized)	wisconsin
Occupation	Machinist
Township / Ward	Chicago City
Est. Birth Year	~1885

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
Evelyn Koch	Daughter	—	24	~1916
John Koch	Head	—	55	~1885
Alice Koch	Spouse	—	48	~1892

Census Appearances

1920

Cook, Illinois

Head, age 34

Cook, Illinois · implied b. ~1886 — 4 household members

● Primary link · ~Confirmed · 2 sources

XGBoost Household

Surname	Koch
Given Name	John C.
Relationship to Head	Head
Sex	M
Color / Race	White
Age	34
Marital Status	Married
Birthplace	Wisconsin
Father's Birthplace	Wisconsin
Mother's Birthplace	Wisconsin
Occupation	Machinist
Industry	Int Harv Co
Class of Worker	W
Can Read	Yes
Can Write	Yes
Speaks English	Yes
Home Owned/Rented	R
Birth State	Wisconsin
Birth Country	United States
Birthplace (normalized)	wisconsin

1930

Cook, Illinois

Head, age 45

Cook, Illinois · implied b. ~1885 — 2 household members

● Primary link · ~Confirmed · 2 sources

XGBoost Household

Surname	Koch
Given Name	John
Relationship to Head	Head
Sex	M
Color / Race	White
Age	45
Marital Status	Married
Birthplace	Wisconsin
Age at First Marriage	29
Father's Birthplace	Wisconsin
Mother's Birthplace	Wisconsin
Occupation	Machinist
Industry	Steam Railroad
Class of Worker	W
Can Read/Write	Yes
Home Owned/Rented	O
Home Value / Rent	9000
Radio Set	R
Birth State	Wisconsin
Birth Country	United States
Birthplace (normalized)	wisconsin

1940

Cook-County, Illinois

Head, age 55

Cook-County, Illinois · implied b. ~1885 — 3 household members

Surname	Koch
Given Name	John
Relationship to Head	Head
Sex	M
Color / Race	White
Age	55
Marital Status	Married
Birthplace	Wisconsin
1935 Residence (City)	Chicago City
1935 Residence (County)	Cook
Occupation	Machinist
Industry	Surface Lines
Class of Worker	PW
Hours Worked	40
Income (1939)	2080
Highest Grade	H 4
1935 Residence	Same place
Birth State	Wisconsin
Birth Country	United States
Birthplace (normalized)	wisconsin

Model Tree

Linked across censuses

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 55 · b. ~1885 · 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 — Cook-County, Illinois Open full size

Page Contents

40 people indexed on this census page (nara:1940:m-t0627-00940-00699)

Line	Name	Age	Relation	Occupation	Birthplace
41	Mabel G. Daniels	30	Daughter	School Teacher	Illinois
42	J. Robert Daniels	27	Son	Attorney	Illinois
43	Earl Pangborn	14	Nephew	—	Illinois
44	Hyman Kaminsky	43	Head	Manager	Illinois
45	Ida Kaminsky	31	Wife	—	Illinois
46	Leonard Kaminsky	16	Son	—	Illinois
47	Calvin Kaminsky	12	Son	—	Illinois
48	David Kaminsky	10	Son	—	Illinois
49	Joel Kaminsky	2	Son	—	Illinois
50	Christian Thedling	53	Head	Foreman	Illinois
51	Emma Thedling	47	Wife	—	Illinois
52	Frank Page	71	Head	—	Illinois
53	Hattie Page	65	Wife	—	Pennsylvania
54	Clarence Page	45	Head	General Machinist	Illinois
55	Josephine Page	27	Wife	—	Cape Verde Islands
56	John Collett	42	Head	Magneto Foreman	Indiana
57	Selma Collett	41	Wife	—	Illinois
58	Verna Collett	20	Daughter	Machine Operator	Illinois
59	Wallace Collett	17	Son	—	Illinois
60	Guy T. Greene	71	Head	Elevator Operator	Illinois
61	Clara Greene	56	Wife	—	Ohio
62	Miriam Greene	24	Daughter	Personal	Illinois
63	Alice Greene	23	Daughter	Sales Clerk	Illinois
64	Adelaide Greene	21	Daughter	Bank	Illinois
65	Guy E. Greene	17	Son	—	Illinois
66	Walter H. Hatter	41	Head	Foreman	Illinois
67	Beata Hatter	39	Wife	—	Illinois
68	Walter G. Hatter	21	Son	Rate Clerk	Illinois
69	William R. Hatter	19	Son	Laborer	Illinois
70	John Koch THIS PERSON	55	Head	Machinist	Wisconsin
71	Alice Koch	48	Wife	—	Norway
72	Evelyn Koch	24	Daughter	Stenographer	Illinois
73	Frank Thurman	42	Head	General Office Work	Illinois
74	Emily Thurman	40	Wife	—	Illinois
75	Minnie Gulbrandsen	74	Mother-in-law	—	Norway
76	Carl Anderson	35	Head	Milkman	Illinois
77	Elsie Anderson	33	Wife	—	Illinois
78	Joyce Anderson	4	Daughter	—	Illinois
79	Donald Anderson	1	Son	—	Illinois
80	—	None	—	—	—

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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)

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