Self reported. She is my maternal great grandmother on mom's side.
"United States Census, 1870," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M6DY-4Y4 : 12 April 2016), Mabel Smith in household of Charles Smith, Maine, United States; citing p. 8, family 77, NARA microfilm publication M593 (Washington D.C.: National Archives and Records Administration, n.d.); FHL microfilm 552,054.
It may be possible to confirm family relationships with Mabel by comparing test results with other carriers of her mitochondrial DNA.
However, there are no known mtDNA test-takers in her direct maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Mabel: