MD
Mary Duffy — 1930 US Census Record
Linked across censuses1930 United States Federal Census · Philadelphia, Pennsylvania
Our Model Tree links this Mary Duffy across the 1930 and 1940 US Censuses in Philadelphia, Pennsylvania (XGBoost, ~Confirmed) — first a daughter (b.~1912), then head of a 11-person household.
Age 18
b. ~1912
Female
Daughter
Born: Pennsylvania
Single
1930 Census Record Details
| Census Year | 1930 |
| Location | Philadelphia, Pennsylvania |
| Surname | Duffy |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 18 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| Father's Birthplace | Germany |
| Mother's Birthplace | Pennsylvania |
| Additional Details | |
| Can Read/Write | Yes |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
| Township / Ward | Philadelphia |
| Est. Birth Year | ~1912 |
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.
11 people recorded at the same address in the 1930 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Catherine Duffy | Daughter | — | 16 | ~1914 |
| Mary Duffy | Daughter | — | 18 | ~1912 |
| Helen Duffy | Daughter | — | 14 | ~1916 |
| Theresa Duffy | Daughter | — | 12 | ~1918 |
| James Duffy | Head | — | 61 | ~1869 |
| William Duffy | Son | — | 22 | ~1908 |
| Joseph Duffy | Son | — | 10 | ~1920 |
| John Duffy | Son | — | 24 | ~1906 |
| Francis Duffy | Son | — | 20 | ~1910 |
| James Duffy | Son | — | 26 | ~1904 |
| Elizabeth Duffy | Spouse | — | 61 | ~1869 |
Census Appearances
1930
Philadelphia, Pennsylvania
Daughter, age 18
Philadelphia, Pennsylvania · implied b. ~1912 — 11 household members
| Surname | Duffy |
| Given Name | Mary |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 18 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| Father's Birthplace | Germany |
| Mother's Birthplace | Pennsylvania |
| Can Read/Write | Yes |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
1940
Philadelphia-County, Pennsylvania
Other, age 28
Philadelphia-County, Pennsylvania · implied b. ~1912 — 2 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Duffey |
| Given Name | Mary |
| Relationship to Head | Sister |
| Sex | F |
| Color / Race | White |
| Age | 28 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| 1935 Residence (City) | Philadelphia |
| 1935 Residence (County) | Philadelphia |
| Occupation | Book Keeper |
| Industry | Wholesale Sugar Co. |
| Class of Worker | PW |
| Hours Worked | 40 |
| Income (1939) | 884 |
| Highest Grade | No 8 |
| 1935 Residence | Same house |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
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 Duffy across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Duffy
Daughter · 1930 · age 18 · b. ~1912 · Pennsylvania
★ You are viewing this record
Sibling
Helen Duffy
Sibling · 1930 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Theresa Duffy
Sibling · 1930 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
John Duffy
Sibling · 1930 · age 24
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
William Duffy
Sibling · 1930 · age 22
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
James Duffy
Sibling · 1930 · age 26
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Catherine Duffy
Sibling · 1930 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Joseph Duffy
Sibling · 1930 · age 10
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Francis Duffy
Sibling · 1930 · 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
1930 US Federal Census — Philadelphia, Pennsylvania
Open full size
1930 US Federal Census — Philadelphia, Pennsylvania
Page Contents
50 people indexed on this census page (ia:1930:fifteenthcensus00reel2126:0973)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 51 | Catherine | 50 | Wife-H | — | Pennsylvania |
| 52 | Catherine | 24 | Daughter | — | Pennsylvania |
| 53 | Mary | 22 | Daughter | — | Pennsylvania |
| 54 | Helen | 19 | Daughter | Stenographer | Pennsylvania |
| 55 | Anna | 17 | Daughter | Stenographer | Pennsylvania |
| 56 | Margaret | 15 | Daughter | — | Pennsylvania |
| 57 | Lawrence Kearns | 56 | Head | Laborer | Pennsylvania |
| 58 | Mary Kearns | 56 | Wife | — | Pennsylvania |
| 59 | Lawrence Kearns | 26 | Son | Laborer | Pennsylvania |
| 60 | John Kearns | 24 | Son | Laborer | Pennsylvania |
| 61 | Francis Kearns | 21 | Son | Laborer | Pennsylvania |
| 62 | Edward Kearns | 18 | Son | Laborer | Pennsylvania |
| 63 | Elizabeth Steele | 60 | Head | — | Pennsylvania |
| 64 | Elizabeth Steele | 30 | Daughter | Saleslady | Pennsylvania |
| 65 | Anna Steele | 28 | Daughter | Saleslady | Pennsylvania |
| 66 | Margaret Steele | 26 | Daughter | Saleslady | Pennsylvania |
| 67 | James Duffy | 61 | Head | Laborer | Germany |
| 68 | Elizabeth Duffy | 61 | Wife | — | Pennsylvania |
| 69 | James Duffy | 26 | Son | Laborer | Pennsylvania |
| 70 | John Duffy | 24 | Son | Laborer | Pennsylvania |
| 71 | William Duffy | 22 | Son | Laborer | Pennsylvania |
| 72 | Francis Duffy | 20 | Son | Laborer | Pennsylvania |
| 73 | Mary Duffy THIS PERSON | 18 | Daughter | — | Pennsylvania |
| 74 | Catherine Duffy | 16 | Daughter | — | Pennsylvania |
| 75 | Helen Duffy | 14 | Daughter | — | Pennsylvania |
| 76 | Theresa Duffy | 12 | Daughter | — | Pennsylvania |
| 77 | Joseph Duffy | 10 | Son | — | Pennsylvania |
| 78 | James Smith | 22 | Head | Laborer | Pennsylvania |
| 79 | Mary Smith | 22 | Wife | — | Pennsylvania |
| 80 | James Smith | 1 | Son | — | Pennsylvania |
| 81 | John Smith | 0 | Son | — | Pennsylvania |
| 82 | William Smith | 58 | Head | Laborer | Pennsylvania |
| 83 | Mary Smith | 58 | Wife | — | Pennsylvania |
| 84 | William Smith | 26 | Son | Laborer | Pennsylvania |
| 85 | John Smith | 24 | Son | Laborer | Pennsylvania |
| 86 | James Smith | 22 | Son | Laborer | Pennsylvania |
| 87 | Francis Smith | 20 | Son | Laborer | Pennsylvania |
| 88 | Mary Smith | 18 | Daughter | — | Pennsylvania |
| 89 | Catherine Smith | 16 | Daughter | — | Pennsylvania |
| 90 | Helen Smith | 14 | Daughter | — | Pennsylvania |
| 91 | Theresa Smith | 12 | Daughter | — | Pennsylvania |
| 92 | Joseph Smith | 10 | Son | — | Pennsylvania |
| 93 | James Mcdevitt | 57 | Head | Laborer | Pennsylvania |
| 94 | Mary Mcdevitt | 57 | Wife | — | Pennsylvania |
| 95 | James Mcdevitt | 26 | Son | Laborer | Pennsylvania |
| 96 | John Mcdevitt | 24 | Son | Laborer | Pennsylvania |
| 97 | William Mcdevitt | 22 | Son | Laborer | Pennsylvania |
| 98 | Francis Mcdevitt | 20 | Son | Laborer | Pennsylvania |
| 99 | Mary Mcdevitt | 18 | Daughter | — | Pennsylvania |
| 100 | Catherine Mcdevitt | 16 | Daughter | — | Pennsylvania |
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)