"New York State Census, 1865," database with images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/QVNV-3QPV : accessed 5 June 2017), Mary Steers in household of Eadward Steers, District 02, Ward 18, Brooklyn, Kings, New York, United States; citing source p. 29, line 11, household ID 185, county clerk, board of supervisors and surrogate court offices from various counties. Utica and East Hampton Public Libraries, New York; FHL microfilm 1,930,210.
"United States Census, 1870," database with images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MFLT-ZS3 : 17 October 2014), Mary Steers in household of Edward Steers, Virginia, United States; citing p. 4, family 22, NARA microfilm publication M593 (Washington D.C.: National Archives and Records Administration, n.d.); FHL microfilm 553,144.
It may be possible to confirm family relationships with Mary 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 Mary: