St. Mary's Assumption Church, New Orleans, By Infrogmation of New Orleans - Photo by Infrogmation, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=3212501
St. Mary is the Catholic parish church in New Orleans across the street from St. Alphonsus Catholic parish church. The church was built by German immigrants. As the churches were built, the Irish and German immigrants tried to outdo one another. The two groups refused to go to Mass with each other even though the same priests said Mass at both churches.
In The Lives of the Mayfair Witches, St. Mary's Assumption is the home parish of the First Street Mayfairs, and the location for Rowan and Micheal's wedding.