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Mary Monahan — 1930 US Census Record
Linked across censuses1930 United States Federal Census · San Francisco, California
Our Model Tree links this Mary Monahan across the 1930 and 1940 US Censuses in San Francisco, California (XGBoost, ~Confirmed) — first a daughter (b.~1910), then head of a 8-person household.
Age 20
b. ~1910
Female
Daughter
Born: California
Single
1930 Census Record Details
| Census Year | 1930 |
| Location | San Francisco, California |
| Surname | Monahan |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 20 |
| Marital Status | Single |
| Birthplace | California |
| Father's Birthplace | Free State |
| Mother's Birthplace | California |
| Additional Details | |
| Occupation | none |
| Can Read/Write | Yes |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
| Township / Ward | San Francisco |
| Est. Birth Year | ~1910 |
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 1930 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| William Monahan | Son | — | 26 | ~1904 |
| Francis Monahan | Son | — | 16 | ~1914 |
| Doreen Monahan | Daughter | — | 9 | ~1921 |
| Mary Monahan | Daughter | — | 20 | ~1910 |
| William Monahan | Head | — | 55 | ~1875 |
| Thomas Monahan | Son | — | 21 | ~1909 |
| Edgar Monahan | Son | — | 24 | ~1906 |
| Sarah Monahan | Daughter | — | 17 | ~1913 |
Census Appearances
1930
San Francisco, …
Daughter, age 20
San Francisco, California · implied b. ~1910 — 8 household members
| Surname | Monahan |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 20 |
| Marital Status | Single |
| Birthplace | California |
| Father's Birthplace | Free State |
| Mother's Birthplace | California |
| Occupation | none |
| Can Read/Write | Yes |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
1940
San-Francisco-County, California
Daughter, age 30
San-Francisco-County, California · implied b. ~1910 — 7 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | MINAHAN |
| Given Name | MARY A. |
| Relationship to Head | DAUGHTER |
| Sex | F |
| Color / Race | White |
| Age | 30 |
| Marital Status | Single |
| Birthplace | CALIFORNIA |
| 1935 Residence (City) | SAN FRANCISCO |
| 1935 Residence (County) | SAN FRANCISCO |
| Occupation | TYPIST |
| Industry | INSURANCE CO |
| Class of Worker | PW |
| Hours Worked | 38 |
| Income (1939) | 1165 |
| Highest Grade | C 1 |
| 1935 Residence | Same place |
| Birth State | California |
| Birth Country | United States |
| Birthplace (normalized) | california |
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 Monahan across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Monahan
Daughter · 1930 · age 20 · b. ~1910 · California
★ You are viewing this record
Sibling
Francis Monahan
Sibling · 1930 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Doreen Monahan
Sibling · 1930 · age 9
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Edgar Monahan
Sibling · 1930 · age 24
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
William Monahan
Sibling · 1930 · age 26
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Sarah Monahan
Sibling · 1930 · age 17
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Thomas Monahan
Sibling · 1930 · age 21
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 — San Francisco, California
Open full size
1930 US Federal Census — San Francisco, California
Page Contents
50 people indexed on this census page (ia:1930:californiacensus00reel201:0105)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Thomas Mc Donald | 56 | Head | Contractor | California |
| 2 | Mae J. Mc Donald | 52 | Wife | None | Free State |
| 3 | Stephen Elliott | 44 | Head | None | England |
| 4 | James D. Elliott | 18 | Son | None | California |
| 5 | Milton T. Leith | 26 | Roomer | Clerk | Washington |
| 6 | Lewis T. James | 23 | Roomer | Salesman | Kansas |
| 7 | Robt. J. Payne | 52 | Head | Salesman | New York |
| 8 | Isabelle Payne | 46 | Wife | None | New York |
| 9 | Robt. Payne | 18 | Son | None | California |
| 10 | Claude Tidwell | 28 | Head | Clerk | Texas |
| 11 | Clarabelle Tidwell | 22 | Wife | None | Kansas |
| 12 | Claudia Tidwell | 9 | Daughter | None | California |
| 13 | Thomas Dalkie | 61 | Head | Broker | California |
| 14 | Laura Dalkie | 53 | Wife | None | California |
| 15 | Lucy Dalkie | 19 | Daughter | None | California |
| 16 | Madeline Dalkie | 17 | Daughter | None | California |
| 17 | Harley Dalkie | 13 | Son | None | California |
| 18 | Emil Stern | 36 | Head | Doctor | Kentucky |
| 19 | Grace Stern | 38 | Wife | None | California |
| 20 | Marilyn Stern | 7 | Daughter | None | California |
| 21 | Mildred Stern | 5 | Daughter | None | California |
| 22 | Ruth Stern | 3 | Daughter | None | California |
| 23 | Edith Martin | 26 | Lodger | Secretary | California |
| 24 | Harry Watson | 26 | Head | Clerk | California |
| 25 | Stella Watson | 21 | Wife | None | California |
| 26 | Wallace Watson | 3 | Son | None | California |
| 27 | William Monahan | 55 | Head | Officer | Free State |
| 28 | William Monahan | 26 | Son | Motorman | California |
| 29 | Edgar Monahan | 24 | Son | Mechanic | California |
| 30 | Thomas Monahan | 21 | Son | Laborer | California |
| 31 | Mary Monahan THIS PERSON | 20 | Daughter | None | California |
| 32 | Sarah Monahan | 17 | Daughter | None | California |
| 33 | Francis Monahan | 16 | Son | None | California |
| 34 | Doreen Monahan | 9 | Daughter | None | California |
| 35 | John Sims | 41 | Head | Agent | Canada |
| 36 | Gladys Sims | 35 | Wife | None | Nebraska |
| 37 | John Sims | 12 | Son | None | Wyoming |
| 38 | Mildred Sims | 11 | Daughter | None | Wyoming |
| 39 | Helen Sims | 4 | Daughter | None | Hawaii |
| 40 | Walter Straus | 49 | Head | Salesman | Germany |
| 41 | Marie Straus | 42 | Wife | None | California |
| 42 | Fred Straus | 21 | Son | Salesman | California |
| 43 | Elsa Straus | 12 | Daughter | None | California |
| 44 | John Manning | 19 | Roomer | Clerk | California |
| 45 | Lanka Borel | 73 | Head | None | California |
| 46 | Ellen Borel | 54 | Daughter | None | California |
| 47 | Frank Borel | 53 | Son | Manager | California |
| 48 | John G. Gordon | 21 | Roomer | Stock Clerk | California |
| 49 | Albert Schilliger | 54 | Head | Salesman | Switzerland |
| 50 | Caroline Schilliger | 53 | Wife | None | Switzerland |
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)