The Grupe Family Letters is a collection of 22 letters mostly sent to immigrant Marie Franziska Elisabeth Grupe (1825–1923) between 1898 and 1919. Marie Grupe was born in 1825 in Hamburg, Germany, and christened with her mother's last name Uphoff; her father was reportedly a man named Johann Carl Friedrick Kreplin, and she used this last name after immigrating to the United States in 1850. Later that same year, in New York City, she married Charles (or Carl) Grupe (1826–1893), a shoemaker and farmer who was an immigrant from Hanover. Later in the decade the couple settled in New Canaan, Connecticut, where she would live for the rest of her life. The letters were written to Marie Grupe by Gustave Grupe (1847–1930), a nephew of Charles Grupe, who was a master mason in Hamburg.