St. Mary Summer, 1998 Welcome to the St. Mary Congregation portal of the Omnibus Site. St. Mary is located in Richfield, Washington County, Wisconsin, USA on Hillside Road near Pioneer Road. Here you will find the history of the congregation which began in 1854 and those who were the congregation, that is, the individuals who chose for their remains to be cherished by the Blessed Virgin Mary and placed in her cemetery.