MM
Mary Mcdonnell — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Cascade-County, Montana
Our Model Tree links this Mary Mcdonnell across the 1930 and 1940 US Censuses in Cascade-County, Montana (XGBoost, ~Confirmed) — first a daughter (b.~1921), then head of a 6-person household.
Age 19
b. ~1921
Female
Daughter
Born: Montana
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Cascade-County, Montana |
| Surname | McDonnell |
| Given Name | Mary F. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 19 |
| Marital Status | Single |
| Birthplace | Montana |
| 1935 Residence (City) | Great Falls City |
| 1935 Residence (County) | Cascade |
| Additional Details | |
| Income (1939) | 0 |
| Highest Grade | C 1 |
| 1935 Residence | Same place |
| Birth State | Montana |
| Birth Country | United States |
| Birthplace (normalized) | montana |
| Township / Ward | Great Falls City |
| Est. Birth Year | ~1921 |
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.
6 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to Mary | Age | Birth yr |
|---|---|---|---|---|
| Frances Mcdonnell | Daughter | — | 13 | ~1927 |
| Patricia Mcdonnell | Daughter | — | 17 | ~1923 |
| Mary Mcdonnell | Daughter | — | 19 | ~1921 |
| Leo Mcdonnell | Head | — | 53 | ~1887 |
| Frances Mcdonnell | Spouse | — | 53 | ~1887 |
| Lawrence Mcdonnell | Son | — | 18 | ~1922 |
Census Appearances
1930
Cascade, Montana
Daughter, age 9
Cascade, Montana · implied b. ~1921 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | McDonnell |
| Given Name | Mary F |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 9 |
| Marital Status | Single |
| Birthplace | Montana |
| Father's Birthplace | Iowa |
| Mother's Birthplace | New York |
| Birth State | Montana |
| Birth Country | United States |
| Birthplace (normalized) | montana |
1940
Cascade-County, Montana
Daughter, age 19
Cascade-County, Montana · implied b. ~1921 — 6 household members
| Surname | McDonnell |
| Given Name | Mary F. |
| Relationship to Head | Daughter |
| Sex | F |
| Color / Race | White |
| Age | 19 |
| Marital Status | Single |
| Birthplace | Montana |
| 1935 Residence (City) | Great Falls City |
| 1935 Residence (County) | Cascade |
| Income (1939) | 0 |
| Highest Grade | C 1 |
| 1935 Residence | Same place |
| Birth State | Montana |
| Birth Country | United States |
| Birthplace (normalized) | montana |
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 Mcdonnell across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
Mary Mcdonnell
Daughter · 1940 · age 19 · b. ~1921 · Montana
★ You are viewing this record
Sibling
Lawrence Mcdonnell
Sibling · 1940 · age 18
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Frances Mcdonnell
Sibling · 1940 · age 13
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Patricia Mcdonnell
Sibling · 1940 · age 17
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 — Cascade-County, Montana
Open full size
1940 US Federal Census — Cascade-County, Montana
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-02214-00798)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Ruth M. B. Peterson | 34 | Wife | — | Minnesota |
| 2 | David Peterson | 9 | Son | — | Michigan |
| 3 | Victor Peterson | 5 | Son | — | Canada |
| 4 | Jerry Peterson | 2 | Son | — | Montana |
| 5 | Mary Ann Metcalf | 18 | Servant | Servant | Montana |
| 6 | Robert V. Shelton | 48 | Head | Supervisor | Minnesota |
| 7 | Ethel A. Shelton | 32 | Wife | — | Washington |
| 8 | Hellman Kaufman | 45 | Head | Laborer | Wisconsin |
| 9 | Mary A. B. Kaufman | 54 | Wife | — | Missouri |
| 10 | John D. Curtis | 31 | Head | Salesman | Ohio |
| 11 | Grace C. Curtis | 29 | Wife | — | Montana |
| 12 | Barbara Curtis | 2 | Daughter | — | Montana |
| 13 | Jack L. Lansing | 26 | Head | Clerk | Montana |
| 14 | Audrey X. Lansing | 22 | Wife | — | Montana |
| 15 | Arlene A. Lansing | 3 | Daughter | — | Montana |
| 16 | Walter Lansing | 2 | Son | — | Montana |
| 17 | Leo E. Mcdonnell | 53 | Head | Engineer | Iowa |
| 18 | Frances T. Mcdonnell | 53 | Wife | — | New York |
| 19 | Mary F. Mcdonnell THIS PERSON | 19 | Daughter | — | Montana |
| 20 | Lawrence G. Mcdonnell | 18 | Son | New Worker | Montana |
| 21 | Patricia A. Mcdonnell | 17 | Daughter | — | Montana |
| 22 | Frances C. Mcdonnell | 13 | Daughter | — | Montana |
| 23 | Clarence L. Wollaston | 35 | Head | Electrician | South Dakota |
| 24 | Mabel B. Wollaston | 33 | Wife | — | South Dakota |
| 25 | Drew E. Wollaston | 8 | Son | — | Montana |
| 26 | Katherine L. Wollaston | 8 | Daughter | — | Montana |
| 27 | Lois J. Wollaston | 5 | Daughter | — | Montana |
| 28 | Michael J. Wollaston | 1 | Son | — | Montana |
| 29 | William E. Nicholson | 35 | Head | Lineman | Minnesota |
| 30 | Mary E. Nicholson | 36 | Wife | — | Montana |
| 31 | Marie E. Nicholson | 10 | Daughter | — | Montana |
| 32 | Rose Mary Nicholson | 3 | Daughter | — | Montana |
| 33 | Charles A. Larsen | 42 | Head | Sales Manager | Wyoming |
| 34 | Helene Larsen | 38 | Wife | — | Washington |
| 35 | Elinore L. Larsen | 17 | Daughter | — | Montana |
| 36 | Raymond H. Larsen | 14 | Son | C.C.C. | Montana |
| 37 | John S. Killel | 71 | Head | Foreman-Watchman | Illinois |
| 38 | Left Vacant Advice Of Neighbor | None | Neighbor | — | — |
| 39 | Lillian M. Davis | 37 | Head | — | Oklahoma |
| 40 | Michael P. Davis | 5 | Son | — | Montana |
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)