St. Mary's Seminary and Retreat House was founded in 1924 when a group of Franciscans settled in the Lemont area. The current building was originally constructed in 1939 as a theological school, but a decreasing number of vocations forced students to study at other houses of the Franciscan Order in the United States. Though the school program was shut down, the Franciscan Fathers and Brothers continue to serve in retreats and missions, and also give back to the Catholic parishes in the community.
St. Mary's Retreat House is located on the same grounds as the Slovenian Cultural Center. Since its establishment, the house has served as a religious center for people of Slovenian decent.