MM
Mary Mcmahon — 1940 US Census Record
Model Tree available1940 United States Federal Census · Clackamas-County, Oregon
Our Model Tree links this Mary Mcmahon across the 1920, 1930 and 1940 US Censuses in Clackamas-County, Oregon (XGBoost, ~Confirmed), with identified parents James & James — first a daughter (b.~1904), then head of a 3-person household.
Age 36
b. ~1904
Female
Daughter
Born: Oregon
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Clackamas-County, Oregon |
| Surname | McMahon |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 36 |
| Marital Status | Single |
| Birthplace | Oregon |
| 1935 Residence (City) | Gladstone city |
| 1935 Residence (County) | Clackamas |
| Additional Details | |
| Occupation | Bookkeeper |
| Industry | Water Department |
| Class of Worker | PW |
| Hours Worked | 44 |
| Income (1939) | 0 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth State | Oregon |
| Birth Country | United States |
| Birthplace (normalized) | oregon |
| Occupation | Bookkeeper |
| Township / Ward | Gladstone City |
| Est. Birth Year | ~1904 |
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.
3 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Mary Mcmahon | Daughter | — | 36 | ~1904 |
| James Mcmahon | Head | — | 69 | ~1871 |
| Sara Mcmahon | Spouse | — | 66 | ~1874 |
Census Appearances
1920
Clackamas, Oregon
Daughter, age 13
Clackamas, Oregon · implied b. ~1907 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 13 |
| Marital Status | Single |
| Birthplace | Oregon |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Illinois |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Birth State | Oregon |
| Birth Country | United States |
| Birthplace (normalized) | oregon |
1930
Clackamas, Oregon
Daughter, age 25
Clackamas, Oregon · implied b. ~1905 — 3 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McMahon |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 25 |
| Marital Status | Single |
| Birthplace | Oregon |
| Father's Birthplace | Illinois |
| Mother's Birthplace | Illinois |
| Occupation | Waitress |
| Industry | Restaurant |
| Class of Worker | W |
| Can Read/Write | Yes |
| Birth State | Oregon |
| Birth Country | United States |
| Birthplace (normalized) | oregon |
1940
Clackamas-County, Oregon
Daughter, age 36
Clackamas-County, Oregon · implied b. ~1904 — 3 household members
| Surname | McMahon |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 36 |
| Marital Status | Single |
| Birthplace | Oregon |
| 1935 Residence (City) | Gladstone city |
| 1935 Residence (County) | Clackamas |
| Occupation | Bookkeeper |
| Industry | Water Department |
| Class of Worker | PW |
| Hours Worked | 44 |
| Income (1939) | 0 |
| Highest Grade | H 4 |
| 1935 Residence | Same place |
| Birth State | Oregon |
| Birth Country | United States |
| Birthplace (normalized) | oregon |
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 Mary Mcmahon across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: father James Mcmahon (~0.92 confidence) and father James Mcmahon (~0.92 confidence) and father James Mcmahon (~0.92 confidence) and mother Sara Mcmahon (~0.92 confidence) and mother Sarah Mcmahon (~0.92 confidence). The pedigree spans 1 generation with 5 identified ancestors.
Show:
Gen 1
Parents
confidence ≈ 0.92
Father
James Mcmahon
b. ~1871
Source father
● Household
· direct · ~0.92
Father
James Mcmahon
b. ~1872
Source father
● Household
· direct · ~0.92
Father
James Mcmahon
b. ~1872
Source father
● Household
· direct · ~0.92
Mother
Sara Mcmahon
b. ~1874
Source mother
● Household
· direct · ~0.92
Mother
Sarah Mcmahon
b. ~1875
Source mother
● Household
· direct · ~0.92
This person
Anchor record
Mary Mcmahon
Daughter · 1940 · age 36 · b. ~1904 · Oregon
★ You are viewing this record
Confirmed / household (~0.90+)
Probable / derived (~0.65–0.89)
Candidate (<0.65, unverified)
Original Census Page
1940 US Federal Census — Clackamas-County, Oregon
Open full size
1940 US Federal Census — Clackamas-County, Oregon
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-03354-00612)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Albert Mabee | 66 | Head | — | Iowa |
| 2 | Etna Mabee | 51 | Wife | — | Missouri |
| 3 | Alberta Mabee | 31 | Daughter | Examiner | Missouri |
| 4 | Etna Mabee | 26 | Daughter | Inspector & Boxer | Washington |
| 5 | Virginia Mabee | 23 | Daughter | Stenographer | Oregon |
| 6 | Laurel Sievers | 29 | Head | Machine Tender | Washington |
| 7 | Virginia Sievers | 20 | Wife | — | Oregon |
| 8 | Jacquelyn Sievers | 3 | Daughter | — | Oregon |
| 9 | Russel M. Griffin | 37 | Head | Service Station Operator | Nebraska |
| 10 | Lilian C. Griffin | 32 | Wife | Bookkeeper & Clerk | Washington |
| 11 | Frank R. Griffin | 11 | Son | — | California |
| 12 | Donald L. Griffin | 10 | Son | — | California |
| 13 | Glenn A. Griffin | 8 | Son | — | California |
| 14 | Martha Stevens | 56 | Head | Practical Nurse | Iowa |
| 15 | Clarence Stevens | 28 | Son | Paper Machine Helper | Washington |
| 16 | Hugh M. Stevens | 20 | Son | Truck Driver | Oregon |
| 17 | William H. Mcmahon | 45 | Head | Salesman | South Dakota |
| 18 | Verna A. Mcmahon | 49 | Wife | — | Washington |
| 19 | James O. Mcmahon | 69 | Head | Carpenter | Illinois |
| 20 | Sara Mcmahon | 66 | Wife | — | Illinois |
| 21 | Mary Mcmahon THIS PERSON | 36 | Daughter | Bookkeeper | Oregon |
| 22 | Carl W. Pallock | 30 | Head | Constable | Oregon |
| 23 | Lucille Pallock | 28 | Wife | — | Oregon |
| 24 | Sandra Pallock | 6 | Daughter | — | Oregon |
| 25 | Charles H. Mccurdy | 77 | Head | — | Ohio |
| 26 | Jennie Mccurdy | 69 | Wife | — | Kansas |
| 27 | George A. Mccurdy | 50 | Brother | — | Ohio |
| 28 | Thomas Linn | 56 | Head | Carpenter | Oregon |
| 29 | Leona M. Linn | 51 | Wife | — | Nebraska |
| 30 | Roman Miller | 33 | Head | Road Project | Ohio |
| 31 | Josephine Miller | 29 | Wife | — | Ohio |
| 32 | Roy Miller | 12 | Son | — | Ohio |
| 33 | Glenn Miller | 8 | Son | — | Ohio |
| 34 | Wayne Miller | 5 | Son | — | Ohio |
| 35 | Dorothy Miller | 2 | Daughter | — | Oregon |
| 36 | Eela Jeffs | 58 | Head | House Work | Idaho |
| 37 | Nolan Jeffs | 22 | Son | Apprentice Painter | Idaho |
| 38 | Roy Warthen | 53 | Head | Molder | Kansas |
| 39 | Waneta Warthen | 42 | Wife | — | California |
| 40 | Robert S. Fenlon | 26 | Son-in-law | Clerical Work | Michigan |
Pedigree Summary
Mary
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)