St. Mary’s Church was first erected in Unionville in 1876 by the Rev. Bernard O’Reilly Sheridan. Unfortunately, fire proved to be a swift villain in a total razing of the church building only eight years after its completion. Rebuilt in 1885, it again burned to the ground, this time in 1891. The third attempt, thankfully, for some time longer. Between 1922 and 1925 the building was expanded to accommodate the sacristy. An additional steeple was part of the building until lightning struck it in 1936 and, deemed unsafe, that steeple was removed. In March, 1949, a five year old playing with matches started a fire that caused extensive damage to the left front corner of the building at the choir loft level and the front entry.
The building that parishioners called "St. Mary's" for over past 100 years, therefore, certainly went through these many fixes and refurbishments throughout that time. The interior, too, went through it's own changes, most notably in an effort to facilitate the new ritual of the Mass promoted by the Second Vatican Council.
Then, following the turn of the 21st century, the decision was made by the parish that, once again, a new church was required to serve the needs of the community. The beautiful, new building, built directly across the street, was dedicated in 2004 and has served the needs of the St. Mary Star of the Sea community wonderfully in the years since. As they have since their beginning, the Catholics of Unionville has persevered and found the beauty in something new, recognizing the importance of the Church and their faith even when changes and time require a change in the church building where that faith will be formed and lived.