Margaret Brennan — 1940 US Census Record

Model Tree available

1940 United States Federal Census · Cook-County, Illinois

Our Model Tree links this Margaret Brennan across the 1920, 1930 and 1940 US Censuses in Cook-County, Illinois (XGBoost, ~Confirmed), with identified parents Catherine — first a head (b.~1879), then head of a 4-person household.

Age 61 b. ~1879 Female Head Born: Illinois Widowed

1940 Census Record Details

Census Year	1940
Location	Cook-County, Illinois
Surname	Brennan
Given Name	Margaret
Relationship to Head	Head
Sex	F
Color / Race	White
Age	61
Marital Status	Widowed
Birthplace	Illinois
1935 Residence (City)	Chicago
1935 Residence (County)	Cook
Additional Details
Class of Worker	0
Hours Worked	0
Highest Grade	No 8
1935 Residence	Same place
Birth State	Illinois
Birth Country	United States
Birthplace (normalized)	illinois
Township / Ward	Chicago
Est. Birth Year	~1879

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.

4 people recorded at the same address in the 1940 census.

Name	Relation to head	Relative to Margaret	Age	Birth yr
Margaret Brennan	Head	—	61	~1879
Robert Brennan	Son	—	25	~1915
Harry Brennan	Spouse	—	68	~1872
Mary Brennan	Daughter	—	28	~1912

Census Appearances

1920

Cook, Illinois

Daughter, age 38

Cook, Illinois · implied b. ~1882 — 4 household members

● Primary link · ~Confirmed · 2 sources

XGBoost Household

Surname	Brennan
Given Name	Margaret
Relationship to Head	Daughter
Sex	F
Color / Race	White
Age	38
Marital Status	Single
Birthplace	Illinois
Father's Birthplace	Ireland
Mother's Birthplace	Ireland
Occupation	Teacher
Industry	School
Class of Worker	W
Can Read	Yes
Can Write	Yes
Speaks English	Yes
Birth State	Illinois
Birth Country	United States
Birthplace (normalized)	illinois

1930

Cook, Illinois

Other, age 50

Cook, Illinois · implied b. ~1880 — 2 household members

● Primary link · ~Confirmed · 2 sources

XGBoost Household

Surname	Brennan
Given Name	Margaret
Relationship to Head	Sister
Sex	F
Color / Race	White
Age	50
Marital Status	Single
Birthplace	Illinois
Father's Birthplace	Ireland
Mother's Birthplace	Ireland
Occupation	Teacher
Industry	Public School
Class of Worker	W
Can Read/Write	Yes
Birth State	Illinois
Birth Country	United States
Birthplace (normalized)	illinois

1940

Cook-County, Illinois

Head, age 61

Cook-County, Illinois · implied b. ~1879 — 4 household members

Surname	Brennan
Given Name	Margaret
Relationship to Head	Head
Sex	F
Color / Race	White
Age	61
Marital Status	Widowed
Birthplace	Illinois
1935 Residence (City)	Chicago
1935 Residence (County)	Cook
Class of Worker	0
Hours Worked	0
Highest Grade	No 8
1935 Residence	Same place
Birth State	Illinois
Birth Country	United States
Birthplace (normalized)	illinois

Model Tree

Model Tree available

Our Model Tree links Margaret Brennan across 3 US Census years (1920, 1930 and 1940) in 2 locations, using XGBoost record linkage. Identified parents: mother Catherine Brennan (~0.92 confidence). The pedigree spans 1 generation with 1 identified ancestor.

Show:

Gen 1 Parents confidence ≈ 0.92

Mother

Catherine Brennan

b. ~1855

Source mother

● Household · direct · ~0.92

This person

Anchor record

Margaret Brennan

Head · 1940 · age 61 · b. ~1879 · 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

Page Contents

40 people indexed on this census page (nara:1940:m-t0627-00982-00211)

Line	Name	Age	Relation	Occupation	Birthplace
41	James Simpson	18	Son	—	Illinois
42	Margaret A Simpson	16	Daughter	—	Illinois
43	Malcolm Simpson	15	Son	—	Illinois
44	Mary Simpson	12	Daughter	—	Illinois
45	Catherine Simpson	9	Daughter	—	Illinois
46	Michael Maloney	57	Head	Steam Layer	Irish Free State
47	Anna B Maloney	51	Wife	—	Irish Free State
48	Mary Maloney	28	Daughter	Saleslady	Illinois
49	James Kurz	51	Head	Checker	Irish Free State
50	Margaret Kurz	51	Wife	—	Illinois
51	Margaret A Kurz	22	Daughter	Candy Maker	Illinois
52	Alfred Kurz	19	Son	Bus Boy	Illinois
53	Thomas Kurz	15	Son	—	Illinois
54	Catherine Murphy	45	Sister	Candy Maker	Illinois
55	Mary Casey	69	Head	—	Irish Free State
56	Hugh Mckillop	45	Lodger	Elevator Operator	Penn State
57	Mary Gracie	44	Head	—	Italy
58	Jane Vallis	49	Head	Coat Maker	Italy
59	Jerry Vallis	23	Son	Clerk	Illinois
60	Michael Vallis	20	Son	Clerk	Illinois
61	Theresa Vallis	18	Daughter	Stenographer	Illinois
62	Rudolph Vallis	15	Son	—	Illinois
63	Lola Vallis	7	Daughter	—	Illinois
64	Frank Viehman	51	Head	Asst. Buyer	Missouri
65	Helen Viehman	51	Wife	—	Illinois
66	Frank Jr Viehman	29	Son	Shipping Clerk	Illinois
67	Robert Viehman	20	Son	—	Illinois
68	Thomas Toomey	54	Head	Laborer	Irish Free State
69	Margaret Toomey	50	Wife	—	Irish Free State
70	John Toomey	32	Son	Clerk Office Work	Illinois
71	Elizabeth Toomey	25	Daughter	Stenographer	Illinois
72	Margaret Brennan THIS PERSON	61	Head	—	Illinois
73	Harry G Brennan	68	Husband	Carpenter	Illinois
74	Robert Brennan	25	Son	Truck Driver	Illinois
75	Mary L Brennan	28	Daughter	—	Illinois
76	Thomas J Maloney	34	Head	Electrician	Iowa
77	Margaret Maloney	31	Wife	—	Illinois
78	Barbara Maloney	8	Son	—	Illinois
79	Mary Lou Maloney	1	Daughter	—	Illinois
80	James Doyle	47	Head	Chauffeur	Illinois

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Pedigree Summary

Margaret

Gen 1 · 1 parents ~0.92

Max depth 4 (1900–1950 window)

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)

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