In 1843, Reverend William P. Hogan conducted the first Mass in Waterford at the Town Hall. Five years later, the inaugural St. Mary of the Assumption Parish Church was built on its original site. In 1858, the Augustinian Order assumed leadership of the parish, with Reverend George Meagher, O.S.A., as the first Pastor. Over the years, the church underwent significant improvements, including the construction of a new church in 1911, blessed by Bishop Burke in 1913. 

In 1951, Very Reverend Francis A. Diehl, O.S.A., became Pastor, leading to the establishment of St. Mary’s School in 1953. Over time, the parish underwent expansions and renovations, including a restoration project for the original church in the 1990s which stands to this day as the parish hall and our schools gymnasium. In 2011, a Capital Campaign funded extensive renovations to the church’s interior and roof repairs, culminating in the celebration of its 100th anniversary in 2013.