Elizabeth Catherine (or Catharine) Rex born in a small town near Gettysburg, Pennsylvania, April 4, 1837.

Elizabeth learned all the jobs of farm work, from the building of stone walls, the clearing of fields, the shearing of sheep and the picking of geese to the spinning of flax and wool, and especially to the caring for sick and wounded animals.

At an early age, became an active worker in the church, leading class meetings, giving Bible readings and teaching in Sunday school.

[4] In 1857, she married Matthias McComsey (1818–1859),[3] of Lancaster, Pennsylvania and within two years, was a mother and a widow.

[1][2] After graduation, she almost immediately opened a dispensary and hospital in Bedford Street, Philadelphia.

[4] In 1872, she was appointed successor to Dr. Ann Preston on the board of attending physicians of the Woman's Hospital of Philadelphia, a position which she held until 1875, when she was appointed resident physician of the New England Hospital for Women and Children in Boston.

From the time of her residency in the New England Hospital, she held the position of senior attending surgeon to that institution.

The surgical work there embraced major as well as minor operations, amputations, abdominal sections, and fractures.

[4][1] Keller spent summer months at her mountain retreat in Jaffrey, New Hampshire.