MD
Mary Duffy — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cook-County, Illinois
Our Model Tree links this Mary Duffy across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed) — first a spouse (b.~1888), then head of a 5-person household.
Age 52
b. ~1888
Female
Spouse
Born: Illinois
Married
1940 Census Record Details
| Census Year | 1940 |
| Location | Cook-County, Illinois |
| Surname | Duffy |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 52 |
| Marital Status | Married |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Additional Details | |
| Highest Grade | G-8 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
| Township / Ward | Chicago |
| Est. Birth Year | ~1888 |
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.
5 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Eileen Duffy | Daughter | — | 18 | ~1922 |
| Patrick Duffy | Head | — | 53 | ~1887 |
| Mary Duffy | Other | — | 21 | ~1919 |
| James Duffy | Son | — | 25 | ~1915 |
| Mary Duffy | Spouse | — | 52 | ~1888 |
Census Appearances
1920
Cook, Illinois
Spouse, age 30
Cook, Illinois · implied b. ~1890 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Duffy |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 30 |
| Marital Status | Married |
| Birthplace | Illinois |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Can Read | Yes |
| Can Write | Yes |
| Speaks English | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1930
Cook, Illinois
Spouse, age 41
Cook, Illinois · implied b. ~1889 — 8 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Duffy |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 41 |
| Marital Status | Married |
| Birthplace | Illinois |
| Age at First Marriage | 22 |
| Father's Birthplace | Ireland |
| Mother's Birthplace | Ireland |
| Can Read/Write | Yes |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
1940
Cook-County, Illinois
Spouse, age 52
Cook-County, Illinois · implied b. ~1888 — 5 household members
| Surname | Duffy |
| Given Name | Mary |
| Relationship to Head | Wife |
| Sex | F |
| Color / Race | White |
| Age | 52 |
| Marital Status | Married |
| Birthplace | Illinois |
| 1935 Residence (City) | Chicago |
| 1935 Residence (County) | Cook |
| Highest Grade | G-8 |
| 1935 Residence | Same place |
| Birth State | Illinois |
| Birth Country | United States |
| Birthplace (normalized) | illinois |
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 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Duffy
Spouse · 1940 · age 52 · b. ~1888 · Illinois
★ 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 — Cook-County, Illinois
Open full size
1940 US Federal Census — Cook-County, Illinois
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-00956-00184)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Vinen Harrison | 22 | Head | Ticket Agent | Pennsylvania |
| 42 | Ruby Harrison | 40 | Mother | — | Pennsylvania |
| 43 | Dolores Harrison | 19 | Sister | Housework | Pennsylvania |
| 44 | Roberta Harrison | 16 | Sister | — | Illinois |
| 45 | Carl Johnson | 50 | Head | Buyer | Nebraska |
| 46 | Bessie Johnson | 45 | Wife | — | Illinois |
| 47 | Carl Jr. Johnson | 22 | Son | Production Mgr | Illinois |
| 48 | Wilbert Johnson | 20 | Son | Production Man | Illinois |
| 49 | Eugene Johnson | 15 | Son | — | Illinois |
| 50 | Betty J. Johnson | 10 | Daughter | — | Illinois |
| 51 | Coy W. Clarke | 36 | Head | Asst Shipping Clk | Indiana |
| 52 | May Clarke | 35 | Wife | Cashier | Illinois |
| 53 | Catherine Clarke | 63 | Mother-in-law | — | Irish Free State |
| 54 | Patrick J. Duffy | 53 | Head | Office Worker | Illinois |
| 55 | Mary Duffy THIS PERSON | 52 | Wife | — | Illinois |
| 56 | James P. Duffy | 25 | Son | Stock Clerk | Illinois |
| 57 | Mary Virginia Duffy | 21 | Daughter-in-law | File Clerk | Illinois |
| 58 | Eileen Duffy | 18 | Daughter | Stenographer | Illinois |
| 59 | George Bell | 42 | Head | Peddler | Illinois |
| 60 | Jack Anderson | None | Head | — | — |
| 61 | Robert Barnes | 48 | Head | Interior Decorator | England |
| 62 | Maude Barnes | 47 | Wife | — | England |
| 63 | Roy Loytal | 44 | Head | Car Salesman | Indiana |
| 64 | Mary Loytal | 42 | Wife | Saleslady | Missouri |
| 65 | Bernard Loytal | 16 | Son | — | Illinois |
| 66 | Margaret E. Loytal | 12 | Daughter | — | Illinois |
| 67 | Nellie Rouse | 69 | Mother-in-law | — | Missouri |
| 68 | William Leake | 56 | Head | Motorman | Illinois |
| 69 | Emma Leake | 51 | Wife | — | Illinois |
| 70 | Dorothea Leake | 12 | Daughter | — | Illinois |
| 71 | Roy T. Knapp | 36 | Son-in-law | Salesman | Illinois |
| 72 | Naomi Knapp | 32 | Daughter | — | Illinois |
| 73 | Donna Rae Knapp | 1 | Granddaughter | — | Illinois |
| 74 | Austin Johnson | 40 | Head | Draftsman | Illinois |
| 75 | Adelia E. Johnson | 41 | Wife | — | Indiana |
| 76 | Shirley Johnson | 12 | Daughter | — | Illinois |
| 77 | Harry Drakie | 62 | Head | Treasurer | England |
| 78 | Harry Drakie | 57 | Brother | Bookkeeper | England |
| 79 | Beulah Gummie | 59 | Housekeeper | Pr. Family | Indiana |
| 80 | Mary O'Brien | 36 | Head | Waitress | Czechoslovakia |
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)