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William Knapp — 1940 US Census Record

Linked across censuses

1940 United States Federal Census · Jefferson-County, New York

Our Model Tree links this William Knapp across the 1930 and 1940 US Censuses in Jefferson-County, New York (XGBoost, ~Confirmed) — first a son (b.~1923), then head of a 10-person household.

Age 17 b. ~1923 Male Son Born: New York Single

1940 Census Record Details

Census Year	1940
Location	Jefferson-County, New York
Surname	Knapp
Given Name	William A.
Relationship to Head	Son
Sex	M
Color / Race	White
Age	17
Marital Status	Single
Birthplace	New York
1935 Residence (City)	Watertown City
1935 Residence (County)	Jefferson
Additional Details
Highest Grade	H-2
1935 Residence	Same House
Birth State	New York
Birth Country	United States
Birthplace (normalized)	new york
Township / Ward	Watertown City
Est. Birth Year	~1923

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.

10 people recorded at the same address in the 1940 census.

Name	Relation to head	Relative to William	Age	Birth yr
Alza Knapp	Spouse	—	43	~1897
Carl Knapp	Son	—	9	~1931
Mary Knapp	Daughter	—	21	~1919
Donald Knapp	Son	—	5	~1935
William Knapp	Son	—	17	~1923
Arthur Knapp	Son	—	10	~1930
John Knapp	Son	—	7	~1933
Helen Knapp	Daughter	—	19	~1921
Allen Knapp	Son	—	12	~1928
Arthur Knapp	Head	—	49	~1891

Census Appearances

1930

Jefferson, New …

Son, age 7

Jefferson, New York · implied b. ~1923 — 8 household members

● Primary link · ~Confirmed · 2 sources

XGBoost Household

Surname	Knapp
Given Name	William
Relationship to Head	Son
Sex	M
Color / Race	White
Age	7
Marital Status	Single
Birthplace	New York
Father's Birthplace	New York
Mother's Birthplace	New York
Can Read/Write	Yes
Birth State	New York
Birth Country	United States
Birthplace (normalized)	new york

1940

Jefferson-County, New …

Son, age 17

Jefferson-County, New York · implied b. ~1923 — 10 household members

Surname	Knapp
Given Name	William A.
Relationship to Head	Son
Sex	M
Color / Race	White
Age	17
Marital Status	Single
Birthplace	New York
1935 Residence (City)	Watertown City
1935 Residence (County)	Jefferson
Highest Grade	H-2
1935 Residence	Same House
Birth State	New York
Birth Country	United States
Birthplace (normalized)	new york

Model Tree

Linked across censuses

Our Model Tree links William Knapp across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.

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This person

Anchor record

William Knapp

Son · 1940 · age 17 · b. ~1923 · New York

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Sibling

Donald Knapp

Sibling · 1940 · age 5

Source co-child of head (derived)

● Co-child · derived · ~0.88

Sibling

Carl Knapp

Sibling · 1940 · age 9

Source co-child of head (derived)

● Co-child · derived · ~0.88

Sibling

Allen Knapp

Sibling · 1940 · age 12

Source co-child of head (derived)

● Co-child · derived · ~0.88

Sibling

Helen Knapp

Sibling · 1940 · age 19

Source co-child of head (derived)

● Co-child · derived · ~0.88

Sibling

John Knapp

Sibling · 1940 · age 7

Source co-child of head (derived)

● Co-child · derived · ~0.88

Sibling

Mary Knapp

Sibling · 1940 · age 21

Source co-child of head (derived)

● Co-child · derived · ~0.88

Sibling

Arthur Knapp

Sibling · 1940 · age 10

Source co-child of head (derived)

● Co-child · derived · ~0.88

Confirmed / household (~0.90+) Probable / derived (~0.65–0.89) Candidate (<0.65, unverified)

Original Census Page

1940 US Federal Census — Jefferson-County, New York Open full size

Page Contents

40 people indexed on this census page (nara:1940:m-t0627-02545-00592)

Line	Name	Age	Relation	Occupation	Birthplace
41	John Waldron	60	Head	Caretaker	New York
42	Mary C. Waldron	67	Wife	—	England
43	Arthur R. Knapp	49	Head	Asst Supt	New York
44	Alza A. Knapp	43	Wife	—	New York
45	Mary A. Knapp	21	Daughter	Clerk	New York
46	Helen C. Knapp	19	Daughter	Clerk	New York
47	William A. Knapp THIS PERSON	17	Son	—	New York
48	Allen C. Knapp	12	Son	—	New York
49	Arthur A. Knapp	10	Son	—	New York
50	Carl E. Knapp	9	Son	—	New York
51	John D. Knapp	7	Son	—	New York
52	Donald T. Knapp	5	Son	—	New York
53	J. A. Q. Coulter	57	Head	Janitor & Treasurer	New York
54	Marion P. Coulter	60	Wife	—	New York
55	Clarence M. Kendall	52	Head	Manager	New York
56	Florence M. Kendall	44	Wife	—	Canada-English
57	Constance M. Kendall	18	Daughter	—	New York
58	Frederic S. Kendall	16	Son	—	New York
59	Ivan S. Evans	55	Head	Circulation Representative	New York
60	Margaret S. Evans	35	Wife	—	New York
61	Mary F. Evans	6	Daughter	—	New York
62	Edward S. Evans	5	Son	—	New York
63	Evelyn A. Caldwell	19	Servant	Maid	New York
64	G. Gordon Brown	48	Head	Landscape Architect	New York
65	Mary F. Brown	43	Wife	—	New York
66	Elizabeth A. Brown	2	Daughter	—	New York
67	Neil E. Heinrich	38	Head	Cashier	New York
68	Dora F. Heinrich	37	Wife	—	New York
69	Neil F. Heinrich	14	Son	—	New York
70	Noel J. Heinrich	11	Son	—	New York
71	Fred G. Brownell	52	Head	Superintendent	New York
72	Jennie E. Brownell	48	Wife	—	New York
73	Frederick G. Jr. Brownell	20	Son	Clerk	New York
74	Clarence E. Hayes	38	Head	Pharmacist	New York
75	Florence M. Hayes	33	Wife	—	New York
76	Robert C. Hayes	12	Son	—	New York
77	Minnie E. Mchale	18	Servant	Maid - Part-Time	New York
78	Herman H. Ehler	45	Head	Land & Tax Agent	New Jersey
79	Clara M. Ehler	43	Wife	—	New Jersey
80	John L. Warner	54	Head	Purchasing Agent	New York

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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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