Emma Henries was born on May 21, 1849, in Groton, Massachusetts, to Henry C. Henries and Abbie Paine. Her father was a minister who owned $3,000 of real estate and $1,000 of personal property by 1860. The family lived in Groton until the 1850s, when they moved to Lincoln, Maine.
Her father served as a hospital chaplain during the Civil War. She accompanied him to the general hospital in Annapolis, Maryland, and she wrote at least one letter to the relative of a sick soldier.
She married Thomas M. Plaisted on September 9, 1874, and they had at least three children: Ella, born around 1876; Marjorie, born around 1879; and Wilmot, born around 1882. They lived in Lincoln, Maine, and her husband worked as a leather manufacturer. They moved to South Dakota in the early 1880s, and her husband worked as a farmer there. Her husband died on July 11, 1892, and by 1900, she was working as a music teacher in Worcester, Massachusetts. She died of myocardial degeneration on January 9, 1923, in Nether Providence Township, Pennsylvania.