JC
John Callahan — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Baltimore-County, Maryland
Our Model Tree links this John Callahan across the 1930 and 1940 US Censuses in Baltimore-County, Maryland (XGBoost, ~Confirmed) — first a son (b.~1928), then head of a 10-person household.
Age 12
b. ~1928
Male
Son
Born: Maryland
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Baltimore-County, Maryland |
| Surname | Callahan |
| Given Name | John |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Edgemere |
| 1935 Residence (County) | Baltimore |
| Additional Details | |
| Industry | 0 |
| Highest Grade | G 5 |
| 1935 Residence | Same place |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
| Township / Ward | Edgemere |
| Est. Birth Year | ~1928 |
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.
10 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to John | Age | Birth yr |
|---|---|---|---|---|
| Patricia Callahan | Daughter | — | 23 | ~1917 |
| Alma Callahan | Daughter | — | 16 | ~1924 |
| Suzanne Callahan | Daughter | — | 14 | ~1926 |
| Rose Callahan | Daughter | — | 19 | ~1921 |
| Louis Callahan | Head | — | 52 | ~1888 |
| Lula Warthen | Other | — | 35 | ~1905 |
| Eugene Callahan | Son | — | 12 | ~1928 |
| John Callahan | Son | — | 12 | ~1928 |
| Louis Callahan | Son | — | 21 | ~1919 |
| Anna Callahan | Spouse | — | 45 | ~1895 |
Census Appearances
1930
Baltimore, Maryland
Son, age 2
Baltimore, Maryland · implied b. ~1928 — 10 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Calahan |
| Given Name | John F. |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 2 |
| Marital Status | Single |
| Birthplace | Maryland |
| Father's Birthplace | New York |
| Mother's Birthplace | Maryland |
| Can Read/Write | Yes |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
1940
Baltimore-County, Maryland
Son, age 12
Baltimore-County, Maryland · implied b. ~1928 — 10 household members
| Surname | Callahan |
| Given Name | John |
| Relationship to Head | son |
| Sex | M |
| Color / Race | White |
| Age | 12 |
| Marital Status | Single |
| Birthplace | Maryland |
| 1935 Residence (City) | Edgemere |
| 1935 Residence (County) | Baltimore |
| Industry | 0 |
| Highest Grade | G 5 |
| 1935 Residence | Same place |
| Birth State | Maryland |
| Birth Country | United States |
| Birthplace (normalized) | maryland |
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 John Callahan across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
John Callahan
Son · 1940 · age 12 · b. ~1928 · Maryland
★ You are viewing this record
Sibling
Eugene Callahan
Sibling · 1940 · age 12
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Rose Callahan
Sibling · 1940 · age 19
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Alma Callahan
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Suzanne Callahan
Sibling · 1940 · age 14
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Louis Callahan
Sibling · 1940 · age 21
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Patricia Callahan
Sibling · 1940 · age 23
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
1940 US Federal Census — Baltimore-County, Maryland
Open full size
1940 US Federal Census — Baltimore-County, Maryland
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-01507-00481)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 41 | Frank Bancunsky | 12 | son | — | Maryland |
| 42 | Irene Bancunsky | 10 | daughter | — | Maryland |
| 43 | Albert Bancunsky | 7 | son | — | Maryland |
| 44 | Louis H. Callahan | 52 | head | Heater Boss | New York |
| 45 | Anna Callahan | 45 | wife | — | Maryland |
| 46 | Patricia Callahan | 23 | daughter | School Teacher | Maryland |
| 47 | Louis Callahan | 21 | son | Electrician | Maryland |
| 48 | Rose Marie Callahan | 19 | daughter | — | Maryland |
| 49 | Alma Callahan | 16 | daughter | — | Maryland |
| 50 | Suzanne Callahan | 14 | daughter | — | Maryland |
| 51 | John Callahan THIS PERSON | 12 | son | — | Maryland |
| 52 | Eugene Callahan | 12 | son | — | Maryland |
| 53 | Lula Warthen | 35 | sister-in-law | Tipper | Maryland |
| 54 | George Summers | 30 | head | Inspector | New York |
| 55 | Meredith Summers | 28 | wife | — | Pennsylvania |
| 56 | Eugene Summers | 10 | son | — | West Virginia |
| 57 | Louella Summers | 8 | daughter | — | West Virginia |
| 58 | Geraldine Summers | 6 | daughter | — | Maryland |
| 59 | Harry Summers | 4 | son | — | Maryland |
| 60 | Edward Mc Lyman | 33 | head | Combustion Engineer | Maryland |
| 61 | Juanita Mc Lyman | 30 | wife | — | Mississippi |
| 62 | Jacqueline Mc Lyman | 11 | daughter | — | Maryland |
| 63 | Donald Mc Lyman | 9 | son | — | Maryland |
| 64 | Ruth Rector | 22 | lodger | Waitress | Pennsylvania |
| 65 | Elizabeth Bethany | 43 | head | — | Hungary |
| 66 | Gabriel Bethany | 23 | son | Soil Checker | West Virginia |
| 67 | Frank Bethany | 22 | son | Millwright | West Virginia |
| 68 | Elizabeth Bethany | 19 | daughter | Waiter | West Virginia |
| 69 | Joseph Bethany | 18 | son | — | New York |
| 70 | Alexander Bethany | 16 | son | — | Ohio |
| 71 | Margaret Bethany | 13 | daughter | — | Ohio |
| 72 | Wilbur Machen | 28 | head | Burner | Maryland |
| 73 | Elizabeth Machen | 28 | wife | — | Maryland |
| 74 | Francis Machen | 5 | son | — | Maryland |
| 75 | Wilma Machen | 1 | daughter | — | Maryland |
| 76 | Annie Burns | 60 | mother-in-law | — | Maryland |
| 77 | August Ludwig | 49 | head | Labor Foreman | Maryland |
| 78 | Addie Ludwig | 48 | wife | — | North Carolina |
| 79 | Margaret Ludwig | 17 | daughter | — | Maryland |
| 80 | Juanita Ludwig | 8 | daughter | — | Maryland |
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)