WF
William Frederick — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Middlesex-County, Massachusetts
Our Model Tree links this William Frederick across the 1930 and 1940 US Censuses in Middlesex-County, Massachusetts (XGBoost, ~Confirmed) — first a son (b.~1927), then head of a 8-person household.
Age 13
b. ~1927
Male
Son
Born: Massachusetts
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Middlesex-County, Massachusetts |
| Surname | Frederick |
| Given Name | William Jr. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | Black |
| Age | 13 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Cambridge City |
| 1935 Residence (County) | Middlesex |
| Additional Details | |
| Highest Grade | No 6 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Township / Ward | Cambridge City |
| Est. Birth Year | ~1927 |
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.
8 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to William | Age | Birth yr |
|---|---|---|---|---|
| Eunice Frederick | Daughter | — | 20 | ~1920 |
| Thelma Frederick | Daughter | — | 29 | ~1911 |
| Agnes Frederick | Spouse | — | 44 | ~1896 |
| Mary Frederick | Daughter | — | 12 | ~1928 |
| William Frederick | Son | — | 13 | ~1927 |
| Walter Frederick | Son | — | 19 | ~1921 |
| William Frederick | Head | — | 61 | ~1879 |
| Clarence Frederick | Son | — | 30 | ~1910 |
Census Appearances
1930
Middlesex, Massachusetts
Son, age 2
Middlesex, Massachusetts · implied b. ~1928 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Fredericks |
| Given Name | William H. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 2 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Canada-English |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1940
Middlesex-County, Massachusetts
Son, age 13
Middlesex-County, Massachusetts · implied b. ~1927 — 8 household members
| Surname | Frederick |
| Given Name | William Jr. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | Black |
| Age | 13 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| 1935 Residence (City) | Cambridge City |
| 1935 Residence (County) | Middlesex |
| Highest Grade | No 6 |
| 1935 Residence | Same place |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
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 Frederick across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
William Frederick
Son · 1940 · age 13 · b. ~1927 · Massachusetts
★ You are viewing this record
Sibling
Thelma Frederick
Sibling · 1940 · age 29
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Mary Frederick
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Clarence Frederick
Sibling · 1940 · age 30
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Walter Frederick
Sibling · 1940 · age 19
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Eunice Frederick
Sibling · 1940 · age 20
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 — Middlesex-County, Massachusetts
Open full size
1940 US Federal Census — Middlesex-County, Massachusetts
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01684-00745)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | John W. Pierce | 78 | Head | Plasterer | Canada English |
| 2 | Annie B. Pierce | 66 | Wife | — | Virginia |
| 3 | Evelyn Small | 70 | Head | — | Virginia |
| 4 | Marie A. Small | 19 | Granddaughter | New Worker | Massachusetts |
| 5 | Mary E. Scott | 63 | Head | Servant | Penn. |
| 6 | Elmer Laks | 63 | Lodger | Porter | Illinois |
| 7 | Barrington Yarborough | 35 | Head | Laborer | North Carolina |
| 8 | Irene Yarborough | 37 | Wife | — | Rhode Island |
| 9 | Elizabeth Yarborough | 12 | Daughter | — | New York |
| 10 | Nancy Yarborough | 5 | Daughter | — | Massachusetts |
| 11 | Ethel M. Trenee | 39 | Head | — | Canada English |
| 12 | Mary Z. Trenee | 14 | Daughter | — | Massachusetts |
| 13 | John M. Trenee | 13 | Son | — | Massachusetts |
| 14 | Eunice P. Trenee | 12 | Daughter | — | Massachusetts |
| 15 | Stansbury A. Trenee | 10 | Son | — | Massachusetts |
| 16 | Manuel A. Trenee | 8 | Son | — | Massachusetts |
| 17 | Alethea Parry | 42 | Head | — | Georgia |
| 18 | Joseph G. Ellis | 58 | Lodger | Kind Haller | Virginia |
| 19 | Charles G. Grintz | 12 | Lodger | — | Massachusetts |
| 20 | Edgar Warner | 14 | Lodger | — | Massachusetts |
| 21 | Nora Sowell | 64 | Head | Seamstress | Massachusetts |
| 22 | James Vaughn | 55 | Brother | Musician | Massachusetts |
| 23 | Isabel Vaughn | 15 | Neice | — | Massachusetts |
| 24 | Ernest Gibson | 54 | Head | Tinsmith | British West Indies |
| 25 | Lorence Gibson | 50 | Wife | — | Florida |
| 26 | Samuel L. Carr | 36 | Lodger | — | British West Indies |
| 27 | Inez S. Carr | 35 | Lodger | — | Florida |
| 28 | William Frederick | 61 | Head | Chauffeur | British West Indies |
| 29 | Agnes Frederick | 44 | Wife | — | British West Indies |
| 30 | Clarence Frederick | 30 | Son | Truck Driver | New York |
| 31 | Thelma Frederick | 29 | Daughter | Seamstress | New York |
| 32 | Eunice Frederick | 20 | Daughter | House Work | Massachusetts |
| 33 | Walter Frederick | 19 | Son | New Worker | Massachusetts |
| 34 | Mary Frederick | 12 | Daughter | — | Massachusetts |
| 35 | William Jr. Frederick THIS PERSON | 13 | Son | — | Massachusetts |
| 36 | Edward Mullins | 46 | Head | Auto Greaser | British West Indies |
| 37 | Edith Mullins | 43 | Wife | — | British West Indies |
| 38 | Charles Berry | 24 | Son | Porter | Massachusetts |
| 39 | Agatha Mullins | 20 | Daughter | — | Massachusetts |
| 40 | Muriel Mullins | 19 | Daughter | New Worker | Massachusetts |
Related Census Records
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)