Margaret was the daughter of William Seddon and Mary Edwards. She married Carl Christian Knoll (son of Joseph J. Knoll and Mary Louise Leider) on 19 Mar 1927 in Albia, Monroe, Iowa. They had a daughter:

Mary Ann (b. ca 31 May 1932 in Goshen,Indiana). She married Robert Wayne Smeltzer on 31 May 1932 in Goshen, Elkhart, Indiana.
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"Iowa, Marriages, 1809-1992," Margaret Seddon, 1927

groom's name: Carl Knoll
groom's birth date: 1904
groom's birthplace: Sheffield, , Iowa
groom's age: 23
bride's name: Margaret Seddon
bride's birth date: 1908
bride's birthplace: Albia, Monroe, Iowa
bride's age: 19
marriage date: 19 Mar 1927
marriage place: Albia, Monroe, Iowa
groom's father's name: J.J. Knoll
groom's mother's name: Mary Laden
bride's father's name: Wm. Seddon
bride's mother's name: Mary Edwards
groom's race: White
groom's marital status: Single
groom's previous wife's name:
bride's race: White
bride's marital status: Single
bride's previous husband's name:
indexing project (batch) number: M02724-5
system origin: Iowa-EASy
source film number: 1887843
reference number: p288 ln12141

Source Citation
"Iowa, Marriages, 1809-1992," index, FamilySearch, Carl Knoll and Margaret Seddon, 19 Mar 1927.
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"United States Census, 1930," Margaret Knoll in household of Carl C Knoll, Goshen, Elkhart, Indiana

name: Margaret Knoll
event: Census
event date: 1930
event place: Goshen, Elkhart, Indiana
gender: Female
age: 21
marital status: Married
race: White
birthplace: Iowa
estimated birth year: 1909
immigration year:
relationship to head of household: Wife
father's birthplace: Iowa
mother's birthplace: Missouri
enumeration district number: 0028
family number: 18
sheet number and letter: 1B
line number: 71
nara publication: T626, roll 585
film number: 2340320
digital folder number: 4584680
image number: 00222

Household Gender Age Birthplace
head Carl C Knoll M 26 Iowa
wife Margaret Knoll F 21 Iowa

Source Citation
"United States Census, 1930," index and images, FamilySearch, Margaret Knoll in household of Carl C Knoll, Goshen, Elkhart, Indiana; citing enumeration district (ED) 0028, sheet 1B, family 18, NARA microfilm publication T626, roll 585.
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"United States Census, 1940," Margaret Knoll in household of Carl Knoll, Ward 2, Goshen City, Elkhart Township, Elkhart, Indiana, United States

name: Margaret Knoll
titles & terms:
event: Census
event year: 1940
event place: Ward 2, Goshen City, Elkhart Township, Elkhart, Indiana, United States
gender: Female
age: 31
marital status: Married
race (original): White
race (standardized): White
relationship to head of household (original): Wife
relationship to head of household (standardized): Wife
birthplace: Iowa
estimated birth year: 1909
residence in 1935: Same Place
enumeration district number: 20-39
family number: 361
sheet number and letter: 15A
line number: 10
nara publication number: T627
nara roll number: 1041
digital folder number: 005459797
image number: 00226

Household Gender Age Birthplace
head Carl Knoll M 35 Iowa
wife Margaret Knoll F 31 Iowa
daughter Mary Ann Knoll F 7 Indiana
brother-in-law William Seddon M 29 Iowa

Source Citation
"United States Census, 1940," index and images, FamilySearch, Margaret Knoll in household of Carl Knoll, Ward 2, Goshen City, Elkhart Township, Elkhart, Indiana, United States; citing enumeration district (ED) 20-39, sheet 15A, family 361, NARA digital publication T627, roll 1041.
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Info provided by F.A.G. member Robert Ashton on 8-1-12:

"Born 1 Aug 1908. Died 20 March 1991. This is from Iowa Births and Social Security Death Index."