Martha was the daughter of Mary Ann (Longley) and Stephen R. Riggs. She was born at the Lac Qui Parle Mission in Chippewa County, MN. Martha spent most of her early childhood at the mission where her family worked as Christian missionaries among the Dakota Indians. In 1854, most of the mission buildings were destroyed by fire. Her father then organized the Hazelwood Mission in Yellow Medicine County, MN, and the family continued their mission work among the Dakotas. During this time, Martha enrolled at the Western Female Seminary (later called Western College for Women) at Oxford, OH. Following her education, she served as an assistant missionary at Hazelwood. Martha was with her family when they and others fled the Hazelwood Mission in the early morning of August 19, 1862, the second day of the Dakota uprising. The group traveled across the prairie in an easterly direction, and, after a week of hardships and danger, they found safety at Henderson, MN. Within a few days, the Riggs family was welcomed by friends at Shakopee, and later at St. Anthony, MN, where they lived for the next three years. Martha helped care for her younger siblings and taught in the local schools, and also at Mankato, MN. In 1866, the family moved to Beloit, WI. On December 18th of that year, Martha married Wyllys K. Morris of Hartford, CT, whom she met in Mankato. Eventually they would have five children. Soon after their marraige, Martha and Wyllys moved to Sterling Township, Blue Earth County, MN, and farmed there for a few years. In the fall of 1870, the couple moved to the Sisseton Indian Reservation, Dakota Territory, to work at the Good Will Mission, recently started by Martha's father. From small beginnings, Martha and Wyllys established a mission boarding school, and remained there for the next 21 years. In 1891, they were called to the Omaha Agency Presbyterian Mission in Nebraska. They spent four years in Nebraska, working among the Omaha and Winnebago Indian children. In 1895 the couple moved to Porcupine on the Pine Ridge Indian reservation in South Dakota. Here they did mission work with the Oglalla Teton Lakota, and it was here that Martha received news of the death of her sister, Isabella, who passed away (1897) in China. At the end of three years in Porcupine, Martha and Wyllys resigned from the Presbyterian Board of Home Missions. For two years following this, they worked in the Oahe School on the Missouri River in central South Dakota. By now, their missionary labors had taken them away from family for several years. In 1900, they returned to Sisseton, SD to be closer to their children and grandchildren. Martha was ill for much of the time during the last few years of her life. She developed a troublesome cough and was eventually confined to her bed. Following a period of declining health, she died at her home in Sisseton on December 4, 1910. Rev. John Eastman, one of her former Good Will mission pupils, said the final funeral prayer for Martha. She was buried beside her parents in Beloit, WI.