St. Mary of the Immaculate Conception is the Roman Catholic sponsor parish for St. Mary's School located next door. St. Mary's is a vibrant parish community with an active Knights of Columbus, Christian Service Center, four masses each weekend including one in Spanish, sponsors Boy Scout Troop 579, religious education programs for all ages, bible study, and more.
The church was designated a Michigan Historical Site in 1971. From the inscription on the marker:
The Roman Catholic Church in Niles traces its origin to the Indian Mission established at nearby Fort St. Joseph in the late 1600's. Reestablished at Bertrand, three miles south of Niles, in the 1830s, the mission moved into town in 1849 and was renamed St. Francis's. In 1866 the cornerstone of the present building was laid and on December 11, 1870, the church was dedicated to St. Mary. Designed by Rufus Rose of Niles with later modifications by Father John Cappon, the church was completed in 1890 with the construction of the gothic tower. Father Cappon, known as the "parish's greatest benefactor," was a Belgian-born priest who served as pastor for over thirty years. He gave generously of his large personal estate for many parish improvements.