The Congregation of the Sisters of St. Mary was established in St. Louis, Missouri by Mary Odilia Berger in 1874. She and some companions had left Germany to provide nursing care to the German immigrant population of the city. Mother Mary Augustine Giesen led a group of sisters to Maryville, Missouri, in 1894. They branched off from the original congregation to focus on providing healthcare to rural areas, and formed the Sisters of St. Francis of Maryville. In 1985 the two congregations merged. The congregation operates 20 hospitals in the Midwestern United States.