Mary, who in most records was listed as Polly, was born in England in 1869 to William Blincow and Betsy Wikes Howe. She immigrated in 1872 and she and her family moved to Nebraska, soon thereafter.
Polly married a York, Nebraska, neighbor, George Blackmore, in 1887. They had eight children, including 5 boys (Henry, Harold, Leonard, George and Clifford) and 3 girls (Ada, Mattie and Reba), born between 1888 and 1904. Two of their boys died young: one as an infant (Leonard) and one at age 10 (Henry Irvin).
This Blackmore family lived in Nebraska until at least 1891. Then by 1893 they lived in Colby County, Kansas. By 1895 they were in Colorado and lived in Granite and Rifle.
Polly died in 1951, two years after George. She was buried in the Rose Hill Cemetery, in Rifle, Colorado, next to her husband.