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William Knapp — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Grundy-County, Illinois
Our Model Tree links this William Knapp across the 1930 and 1940 US Censuses in Grundy-County, Illinois (XGBoost, ~Confirmed) — first a son (b.~1929), then head of a 5-person household.
Age 11
b. ~1929
Male
Son
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Grundy-County, Illinois |
| Surname | Knapp |
| Given Name | William |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 11 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Morris |
| 1935 Residence (County) | Grundy |
| Additional Details | |
| Highest Grade | G 5 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Township / Ward | Morris |
| Est. Birth Year | ~1929 |
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.
5 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to William | Age | Birth yr |
|---|---|---|---|---|
| Virginia Knapp | Daughter | — | 19 | ~1921 |
| Edna Knapp | Spouse | — | 51 | ~1889 |
| Avis Knapp | Head | — | 51 | ~1889 |
| William Knapp | Son | — | 11 | ~1929 |
| Edna Knapp | Son | — | 24 | ~1916 |
Census Appearances
1930
Grundy, Illinois
Son, age 1
Grundy, Illinois · implied b. ~1929 — 7 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Knappe |
| Given Name | William |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 1 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Illinois |
| Occupation | none |
| Can Read/Write | No |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Grundy-County, Illinois
Son, age 11
Grundy-County, Illinois · implied b. ~1929 — 5 household members
| Surname | Knapp |
| Given Name | William |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 11 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Morris |
| 1935 Residence (County) | Grundy |
| Highest Grade | G 5 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
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 William Knapp across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
William Knapp
Son · 1940 · age 11 · b. ~1929 · Illinois
★ You are viewing this record
Sibling
Virginia Knapp
Sibling · 1940 · age 19
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Edna Knapp
Sibling · 1940 · age 24
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 — Grundy-County, Illinois
Open full size
1940 US Federal Census — Grundy-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00809-00288)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Frank J Kelbel | 66 | Head | Club Manager | Illinois |
| 42 | Margaret Kelbel | 52 | Wife | — | Illinois |
| 43 | Anthony Watson | 40 | Head | Proprietor | Illinois |
| 44 | Marie Watson | 35 | Wife | — | Illinois |
| 45 | Joan Watson | 6 | Daughter | — | Illinois |
| 46 | Grace Watson | 2 | Daughter | — | Illinois |
| 47 | Joseph Rettenmayer | 62 | Head | Electrician | Nebraska |
| 48 | Ruth Rettenmayer | 25 | Wife | — | Colorado |
| 49 | John Rettenmayer | 2 | Son | — | Illinois |
| 50 | E. E. Walker | 57 | Head | Proprietor | Illinois |
| 51 | Hannah Walker | 55 | Wife | — | Illinois |
| 52 | Avis Knapp | 51 | Head | Assistant Fireman | Illinois |
| 53 | Edna Knapp | 51 | Wife | — | Illinois |
| 54 | Edna Jr Knapp | 24 | Son | Labor | Illinois |
| 55 | Virginia Knapp | 19 | Daughter | Gen Housework | Illinois |
| 56 | William Knapp THIS PERSON | 11 | Son | — | Illinois |
| 57 | Harvey Washburn | 42 | Head | Letter Carrier | Illinois |
| 58 | Edna Washburn | 39 | Wife | — | Illinois |
| 59 | Janet Washburn | 9 | Daughter | — | Illinois |
| 60 | Charles Washburn | 2 | Son | — | Illinois |
| 61 | Burnette Dorman | 24 | Head | Stenographer | Illinois |
| 62 | Virginia Dorman | 20 | Partner | Stenographer | Illinois |
| 63 | Stephen Watson | 33 | Head | Surveyor | Illinois |
| 64 | Tillie Watson | 26 | Wife | — | Illinois |
| 65 | Adelaide Gebhard | 72 | Head | — | Illinois |
| 66 | Gertrude Erickson | 53 | Maid | Maid | Illinois |
| 67 | Florence Wainwright | 49 | Head | — | Illinois |
| 68 | Addie Hansen | 44 | Sister | — | Illinois |
| 69 | Mary Alice Hansen | 18 | Niece | — | Illinois |
| 70 | Charles David Hansen | 14 | Nephew | — | Illinois |
| 71 | N. G. Taehae | 57 | Head | Medical | Illinois |
| 72 | Edith Taehae | 49 | Wife | — | Illinois |
| 73 | Janice (Al) Taehae | 22 | Daughter | — | Illinois |
| 74 | Nellie M Naden | 72 | Mother | — | Illinois |
| 75 | Mae Thompson | 18 | Maid | Maid | Illinois |
| 76 | — | None | — | — | — |
| 77 | Elliott Pratt | 30 | Head | Medical | Wisconsin |
| 78 | Margaret Pratt | 30 | Wife | — | Illinois |
| 79 | Sue Ann Pratt | 6 | Daughter | — | Illinois |
| 80 | Thelma Erickson | 23 | Maid | Maid | 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)