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Harold Nelson — 1940 US Census Record
Model Tree available1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Harold Nelson across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed), with identified parents Carl & John — first a son (b.~1905), then head of a 12-person household.
Age 35
b. ~1905
Male
Son
Born: Illinois
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Nelson |
| Given Name | Harold |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 35 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Additional Details | |
| Occupation | Radiator Maker |
| Industry | Tractor Co |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 1963 |
| Highest Grade | C-4 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Occupation | Radiator Maker |
| Township / Ward | Chicago |
| Est. Birth Year | ~1905 |
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.
12 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Harold | Age | Birth yr |
|---|---|---|---|---|
| Irene Nelson | Daughter | — | 30 | ~1910 |
| Millard Nelson | Head | — | 55 | ~1885 |
| Mary Nelson | Other | — | 6 | ~1934 |
| Helen Nelson | Other | — | 25 | ~1915 |
| William O'Neil | Other | — | 22 | ~1918 |
| John Nelson | Other | — | 3 | ~1937 |
| James Nelson | Other | — | 1 | ~1939 |
| Mary Nelson | Other | — | ~1940 | |
| Leonard Nelson | Son | — | 26 | ~1914 |
| Harold Nelson | Son | — | 35 | ~1905 |
| Thomas Nelson | Son | — | 22 | ~1918 |
| Helen Nelson | Spouse | — | 55 | ~1885 |
Census Appearances
1920
Cook, Illinois
Son, age 16
Cook, Illinois · implied b. ~1904 — 6 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Nelson |
| Given Name | Harold |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 16 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Sweden |
| Mother's Birthplace | Sweden |
| Industry | Truck |
| Class of Worker | W |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1930
Cook, Illinois
Son, age 25
Cook, Illinois · implied b. ~1905 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Nelson |
| Given Name | Harold E. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | Illinois |
| Father's Birthplace | Sweden |
| Mother's Birthplace | Sweden |
| Occupation | Engineer |
| Industry | Estimating |
| Class of Worker | W |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Cook-County, Illinois
Son, age 35
Cook-County, Illinois · implied b. ~1905 — 12 household members
| Surname | Nelson |
| Given Name | Harold |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 35 |
| Marital Status | Single |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Occupation | Radiator Maker |
| Industry | Tractor Co |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 1963 |
| Highest Grade | C-4 |
| 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 Harold Nelson across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father Carl Nelson (~0.92 confidence) and father John Nelson (~0.92 confidence) and mother Anna Nelson (~0.92 confidence) and mother Helen Nelson (~0.92 confidence) and father Millard Nelson (~0.92 confidence). The pedigree spans 1 generation with 5 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
Carl Nelson
b. ~1863
Source father
● Household
· direct · ~0.92
Father
John Nelson
b. ~1875
Source father
● Household
· direct · ~0.92
Mother
Anna Nelson
b. ~1882
Source mother
● Household
· direct · ~0.92
Mother
Helen Nelson
b. ~1885
Source mother
● Household
· direct · ~0.92
Father
Millard Nelson
b. ~1885
Source father
● Household
· direct · ~0.92
This person
Anchor record
Harold Nelson
Son · 1940 · age 35 · b. ~1905 · Illinois
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Sibling
Leonard Nelson
Sibling · 1940 · age 26
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Irene Nelson
Sibling · 1940 · age 30
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Thomas Nelson
Sibling · 1940 · age 22
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 — 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-t0627-00970-00362)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Millard Nelson | 55 | Head | Supervisor | Ohio |
| 2 | Helen Nelson | 55 | Wife | — | Illinois |
| 3 | Harold Nelson THIS PERSON | 35 | Son | Radiator Maker | Illinois |
| 4 | Irene Nelson | 30 | Daughter | — | Wisconsin |
| 5 | Leonard Nelson | 26 | Son | Machinist | Illinois |
| 6 | Helen M Nelson | 25 | Daughter-in-law | — | Illinois |
| 7 | Thomas Nelson | 22 | Son | Machinist | Illinois |
| 8 | Mary Nelson | 6 | Granddaughter | — | Illinois |
| 9 | John Nelson | 3 | Grandson | — | Illinois |
| 10 | James Nelson | 1 | Grandson | — | Illinois |
| 11 | Mary J Nelson | 0 | Granddaughter | — | Illinois |
| 12 | William O'Neil | 22 | Lodger | Clerk | Illinois |
| 13 | Andrew C Grotz | 38 | Head | Salesman | Illinois |
| 14 | Mary Grotz | 31 | Wife | — | Illinois |
| 15 | Mary Grotz | 12 | Daughter | — | Illinois |
| 16 | Eleanor Grotz | 10 | Daughter | — | Illinois |
| 17 | Joan Grotz | 8 | Daughter | — | Illinois |
| 18 | Lucille Grotz | 5 | Daughter | — | Illinois |
| 19 | Kathleen Grotz | 4 | Daughter | — | Illinois |
| 20 | Andrew E Grotz | 2 | Son | — | Illinois |
| 21 | Theresa Grotz | 0 | Daughter | — | Illinois |
| 22 | Isadore Goodman | 42 | Head | Mechanic | Poland |
| 23 | Ida Goodman | 39 | Wife | — | Russia |
| 24 | George Goodman | 17 | Son | — | Illinois |
| 25 | Shirley Goodman | 11 | Daughter | — | Illinois |
| 26 | Sema Goodman | 7 | Daughter | — | Illinois |
| 27 | Leah Goodman | 5 | Daughter | — | Illinois |
| 28 | Morris Goodman | 65 | Head | Rug Weaving | Poland |
| 29 | Jennie Goodman | 63 | Wife | — | Poland |
| 30 | Mollie Goodman | 25 | Daughter | Trimmer | Illinois |
| 31 | Meyer Goodman | 23 | Son | Sprayer | Illinois |
| 32 | William Wronko | 33 | Head | Machinist | Illinois |
| 33 | Mary Wronko | 32 | Wife | — | Illinois |
| 34 | Lauretta Wronko | 10 | Daughter | — | Illinois |
| 35 | Edwin Wronko | 9 | Son | — | Illinois |
| 36 | Elaine Wronko | 2 | Daughter | — | Illinois |
| 37 | Michael Zahorsky | 50 | Head | Blacksmith | Russia |
| 38 | Mary Zahorsky | 41 | Wife | — | Russia |
| 39 | John Zahorsky | 22 | Son | Machinist | Illinois |
| 40 | Olga Zahorsky | 20 | Daughter | Saleswoman | Illinois |
Pedigree Summary
Harold + 3 siblings
Gen 1 · 5 parents
~0.92
Max depth 4 (1900–1950 window)
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)