The hub of Catholic activity in the 1800s centered at the "Mansion House," the large home owned by the Macomb (Brodhead) family. The "Mansion House" stood on a knoll on East River (between Church Road and Horsemill Road) facing the Canadian shore.
It was at the Brodhead home that the Priest from the Parish of Assumption in Canada came, either by canoe in summer or by walking across the ice in winter. A signal would be given if the priest could be expected that weekend. Father Charles de Preitre was probably the first Priest to celebrate Mass in the "Mansion House." As time passed Priests from Trenton, Wyandotte and Rockwood came to Grosse Ile.