Holy Name of Mary Proto-Cathedral, also known as St. Mary Proto-Cathedral, is a historic Roman Catholic parish church in Sault Ste. Marie, Michigan, United States, that was formerly a cathedral church and the first cathedral, hence "proto-cathedral", of the Roman Catholic Diocese of Marquette. It is the oldest parish and oldest cathedral parish in Michigan, and the third oldest parish in the United States (after those in St. Augustine, Florida and Santa Fe, New Mexico). While the present church edifice, the fifth for the parish, dates from 1881, the parish began in 1668 as a Jesuit mission. It was listed on the National Register of Historic Places in 1984 and designated a State of Michigan historic site in 1989. The proto-cathedral was the (first) cathedral of the Diocese of Marquette when it was denominated the "Diocese of Sault Sainte Marie", which diocesan title is presently that of a titular episcopal see.

Holy Name of Mary was begun by Jesuits in 1668. On January 9, 1857, Bl. Pope Pius IX erected the Diocese of Sault Ste. Marie and the church was named the cathedral church of the new diocese, being the first cathedral in the Upper Peninsula of Michigan. Ven. Irenaeus Frederic Baraga became its first bishop. In 1865, the Diocese of Sault Ste. Marie became the Diocese of Marquette and St. Peter Cathedral in Marquette became the cathedral in its stead.

The present church, the fifth for the parish, was erected in 1881. Canadian architect Joseph Connolly designed it in the Gothic Revival style. The church was extensively remodeled in three phases from the mid-1980s to the mid-1990s. The present rectory was added in 1922.

In 1968 the parish erected the Tower of History as a shrine to the Catholic missionaries who served the community. It was designed to be a part of a larger complex that was to include a community center and a new church edifice. Parish priorities changed and the structure was sold to Sault Historic Sites in 1980, which continues to operate it. Proceeds from the Tower of History still benefit the church.

St. Mary's School was opened 1885. The Sisters of Loretto opened Loretto Academy in 1896 and educated girls from grade school through high school. It became a co-educational high school in 1945. The present school building was built in 1937 and held classes through eighth grade. Both St. Mary's School and Loretto Academy closed in 1971 for financial reasons. The academy building was sold to the local school district. St. Mary's School re-opened in 1993 and serves students from preschool through eighth grade.

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