Margaret is the daughter of Abraham E Johnston and Susan Lucretia McMillen. The last name is recorded as both JOHNSTON and JOHNSON.

West Virginia Birth Index, 1853-1969
-Name: Francis M Johnson
-Gender: Female
-Birth Date: 8 Dec 1856
-Birth Place: Monongalia County, West Virginia
-Father: Abraham Johnson
-Mother: Susen Johnson
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"Our Lathey Family", by Carmen Lathey Barron, July 1981, pp 88-94

"GEORGE WILMAN LATHEY was born May 7, 1878 in Meigs or Noble County, Ohio to Joseph Mark and Emaline (Ward) Lathey. He married Cora Belle Casto February 26, 1899 in Center Point School House in Jackson County. They were married by W. A. Cadia. Cora Belle was born November 2, 1879 in Mason County, West Virginia to George and Margaret Frances (Johnston) Casto".

Mason County, West Virginia Marriage License
-Groom: George W. Casto
-Age: 31
-Birth Place: Jackson Co. (W)Va
-Residence: Meigs County, Ohio

-Bride: Margaret F. Johnston
-Age: 22
-Birth Place: ---
-Residence: Mason County, West Va.
-Marriage Date: 14 Dec 1878
-Marriage Place: Mason County, West Virginia
-Performed by: P.A. Armstrong at the home of the bride's father
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Per the 1880 U.S. Census, George and Margaret Casto resided in Cologne District, Mason County, West Virginia. Three children are listed: Maggie, age 7 & Champ, age 5, (both from George's 1st wife), and Corabell, age 9 months.
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Margaret and George* are known to have 7 children. They are:
-Cora Belle (1879-1956)
-Rosella Ellen "Rosie" (1881-1976)
-Miranda Nicholas (1883-1971)
-Susan Elphia (1886- ? )
-Robert Edward (1891-1958)
-Elsie Myrtle (1893-1957)
-Lestie Gertrude (1896-1985)

*NOTE: George's 2 children with 1st wife, Cassandra Barber, are:
-Margaret May Edmonds (1873-1946)
-"Champ" (1875- ? )
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OHIO Death Certificate: 73987
-Name: Margaret Casto
-Gender: Female
-Death Date: 29 Dec 1928
-Age: 72y 0m 21d
-Marital Status: Married
-Spouse: George W. Casto
-Birth Date: 8 Dec 1856
-Birthplace: West Virginia
-Father: Abraham Johnson
-Father's Birthplace: West Virginia
-Mother: Susan McMillen
-Mother's Birthplace: West Virginia
-Burial Date: 31 Dec 1928
-Cemetery: Oak Grove, Logan, O.
-Occupation: Retired housewife
-Death Place: Marion Township, Franklin, Ohio