WM
William Mcmahon — 1930 US Census Record
Linked across censuses1930 United States Federal Census · Middlesex, Massachusetts
Our Model Tree links this William Mcmahon across the 1920 and 1930 US Censuses in Middlesex, Massachusetts (XGBoost, ~Confirmed) — first a son (b.~1920), then head of a 9-person household.
Age 10
b. ~1920
Male
Son
Born: Massachusetts
Single
1930 Census Record Details
| Census Year | 1930 |
| Location | Middlesex, Massachusetts |
| Surname | McMahon |
| Given Name | William B |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 10 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Additional Details | |
| Can Read/Write | Yes |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
| Township / Ward | Lowell City |
| Est. Birth Year | ~1920 |
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.
9 people recorded at the same address in the 1930 census.
| Name | Relation to head | Relative to William | Age | Birth yr |
|---|---|---|---|---|
| Joseph Mcmahon | Head | — | 45 | ~1885 |
| Naomi Riley | Other | — | 37 | ~1893 |
| Joseph Mcmahon | Son | — | 12 | ~1918 |
| William Mcmahon | Son | — | 10 | ~1920 |
| Blanche Mcmahon | Daughter | — | 6 | ~1924 |
| Blanche Mcmahon | Spouse | — | 47 | ~1883 |
| Lawrence Mcmahon | Son | — | 8 | ~1922 |
| Iris Mcmahon | Daughter | — | 13 | ~1917 |
| Winifred Riley | Other | — | 35 | ~1895 |
Census Appearances
1920
Middlesex, Massachusetts
Other, age
Middlesex, Massachusetts · implied b. ~1920 — 8 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | William T. |
| Relationship to Head | Lodger |
| Sex | M |
| Color / Race | White |
| Age | 0 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Birth State | Massachusetts |
| Birth Country | United States |
| Birthplace (normalized) | massachusetts |
1930
Middlesex, Massachusetts
Son, age 10
Middlesex, Massachusetts · implied b. ~1920 — 9 household members
| Surname | McMahon |
| Given Name | William B |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 10 |
| Marital Status | Single |
| Birthplace | Massachusetts |
| Father's Birthplace | Massachusetts |
| Mother's Birthplace | Massachusetts |
| Can Read/Write | Yes |
| 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 Mcmahon across 2 US Census years (1920 and 1930) in Middlesex, Massachusetts, using XGBoost record linkage.
Show:
This person
Anchor record
William Mcmahon
Son · 1930 · age 10 · b. ~1920 · Massachusetts
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Sibling
Lawrence Mcmahon
Sibling · 1930 · age 8
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Blanche Mcmahon
Sibling · 1930 · age 6
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Iris Mcmahon
Sibling · 1930 · age 13
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Joseph Mcmahon
Sibling · 1930 · age 12
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
1930 US Federal Census — Middlesex, Massachusetts
Open full size
1930 US Federal Census — Middlesex, Massachusetts
Page Contents
43 people indexed on this census page (ia:1930:massachusettscensus00reel920:0385)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Maria H Grinnell | 82 | Head | — | Massachusetts |
| 2 | Mary A Mcadoo | 67 | Roomer | Saleslady | Massachusetts |
| 3 | Alice G Mcadoo | 35 | Roomer | Saleslady | Massachusetts |
| 4 | Richard N Francis | 13 | Roomer | — | Massachusetts |
| 5 | Libbie B Compton | 76 | Head | — | Massachusetts |
| 6 | Thomas G Harvey | 61 | Head | Cigarmaker | Massachusetts |
| 7 | Annie M Harvey | 61 | Wife | — | New Hampshire |
| 8 | Margaret M Harvey | 32 | Daughter | Teacher | Massachusetts |
| 9 | Harold J Harvey | 29 | Son | Watchman | Massachusetts |
| 10 | George F Harvey | 25 | Son | Repairman | Massachusetts |
| 11 | John J Doyle | 46 | Head | Salesman | Massachusetts |
| 12 | Margaret T Doyle | 44 | Wife | Nurse | Massachusetts |
| 13 | Barbara M Doyle | 15 | Daughter | — | Massachusetts |
| 14 | Martha A Doyle | 13 | Daughter | — | Massachusetts |
| 15 | A Josephine Davis | 70 | Roomer | — | New Hampshire |
| 16 | Ethel M Bennett | 44 | Head | — | Maine |
| 17 | Irene G Bennett | 18 | Daughter | — | Massachusetts |
| 18 | Shirley D Bennett | 14 | Daughter | — | Massachusetts |
| 19 | Joseph Mcmahon | 45 | Head | Engineer | Massachusetts |
| 20 | Blanche L Mcmahon | 47 | Wife | — | Massachusetts |
| 21 | Iris D Mcmahon | 13 | Daughter | — | Massachusetts |
| 22 | Joseph J Mcmahon | 12 | Son | — | Massachusetts |
| 23 | William B Mcmahon THIS PERSON | 10 | Son | — | Massachusetts |
| 24 | Lawrence S Mcmahon | 8 | Son | — | Massachusetts |
| 25 | Blanche P Mcmahon | 6 | Daughter | — | Massachusetts |
| 26 | Naomi S Riley | 37 | Sister-in-law | Flyer | Massachusetts |
| 27 | Winifred A Riley | 35 | Sister-in-law | Launderer | Massachusetts |
| 28 | William Zalanskis | 60 | Head | — | Lithuania |
| 29 | Amelia Zalanskis | 70 | Wife | — | Lithuania |
| 30 | Joseph Zalanskis | 27 | Son | Laborer | Massachusetts |
| 31 | Henry Zalanskis | 18 | Son | — | Massachusetts |
| 32 | Mary Zalanskis | 23 | Daughter | Stitcher | Illinois |
| 33 | Annie Stadalniskis | 25 | Daughter | Stitcher | Illinois |
| 34 | Catherine Zalanskis | 19 | Daughter | Hairdresser | Illinois |
| 35 | Helen Stadalniskis | 7 | Granddaughter | — | Massachusetts |
| 36 | Alexander M Macleod | 57 | Head | Dentist | Canada English |
| 37 | Margaret Macleod | 59 | Wife | — | Canada English |
| 38 | Annie Jane Macleod | 23 | Daughter | Accountant | Massachusetts |
| 39 | John F Mcgowan | 35 | Head | Manager | Pennsylvania |
| 40 | Mary E Mcgowan | 32 | Wife | — | Massachusetts |
| 41 | Anna M Roberts | 51 | Head | — | Massachusetts |
| 42 | Walter S Knapp | 61 | Head | Dentist | Massachusetts |
| 43 | Gertrude L Knapp | 54 | Wife | — | Massachusetts |
About This Record & Model Tree
This record was independently indexed by YourRoots from the 1930 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)