In many respects, the history of Holy Trinity Parish is a history of Catholicism on Cape Cod.
The first Holy Trinity Church was built in Harwich Center in 1866, the year following the Civil War. Mass was celebrated there only occasionally when missionary priests traveled the circuit from Sandwich or Boston. Otherwise, the church was seldom used.
Then, in 1904, as the Diocese of Fall River was established by Pope Pius X, Father George F. McGuire came to vitalize the parish. Six years later, Bishop Daniel F. Feehan entrusted the care of the parish to the Sacred Hearts Fathers.
Six years later, in 1910, Father Rupert Jansen was made the first pastor of Harwich and Wellfleet. But in 1911 the church became a mission church of Our Lady of Lourdes parish in Wellfleet. It would be 20 years before Holy Trinity became a parish once again.
In these early years, Holy Trinity served the spiritual needs of Catholics from Yarmouth to Provincetown. By the 1920s, however, due to the deteriorating condition of the church, it was decided to rebuild and enlarge it. The new church, located in Harwich Center, was completed in December 1927.
Only two days after it was completed, on December 18, 1927, a fire broke out and completely destroyed the new church.
Responding as true Christian neighbors, the trustees of the nearby Congregational Church extended the free use of their chapel to the parishioners of Holy Trinity.
To accommodate the large number of visitors during the following summer of 1928, Mass was celebrated in the old Exchange Building, which once stood on Main Street in Harwich Center.
In the meantime, plans were underway for the construction of a new church, but this time located in West Harwich. The new church building was soon completed and subsequently dedicated by Bishop James E. Cassidy on Sunday, August 1, 1930.
The new pastor was Father Arnold H. Derycke, and his district (still, at that time, the Cape Cod Mission) included the churches in Wellfleet, Truro, and North Truro.
In the spring on 1953, Our Lady of the Annunciation chapel was built in Dennisport to accommodate the summer crowds at Holy Trinity.
Then, early on Saturday morning, March 30, 1963, Holy Trinity Church was once again destroyed by fire.
Undaunted by this catastrophe, the parishioners of Holy Trinity rose to meet the need. A new church — the present church that stands today — was completed in the summer of 1965 at a cost of $500,000.
That same year, at the request of the pastor, Sacred Hearts Father Finbar McAloon, eight Sisters of Mercy of the Union arrived to teach in the parish school. For six years, the sisters taught all eight elementary school grades. Due to the declining number of sisters available to teach, the school closed its doors in 1971.
In 1990, after more than 80 years of dedicated service to the Cape Cod Catholic community, the Sacred Hearts Fathers decided to leave all Cape Cod parishes, including Holy Trinity. Bishop Daniel A. Cronin appointed Father Gerald T. Shovelton as pastor, replacing Sacred Hearts Father Gabriel Healy.
In 1994, Holy Trinity School, a diocesan elementary school, was opened using the same facility that housed the parish school in the 1960s. The school was staffed by both lay teachers and Sisters of Mercy, under the leadership of their principal, Sister Carol Clifford. In 2000, thanks to the generosity of an anonymous donor, the school received a large and much needed addition. Holy Trinity School was closed in 2012. The building was then renovated and is now the Parish Center, which houses Religious Education classes, meeting rooms, the parish Thrift Shop, and the Holy Trinity Pre-School.
Also in 2000, the parish began construction of a separate and dedicated perpetual adoration chapel. The building of this new chapel, financed by the same donors who financed the construction of the school addition, was completed in 2001. It replaced the previous perpetual adoration chapel, located in a side chapel of Holy Trinity Church.
In June 2000, Father Shovelton retired and was replaced by Father Thomas L. Rita. In July 2005, Father Edward Healey became pastor. In July 2016 Father Marc Tremblay became pastor and is assisted by two permanent deacons, Deacon Ralph F. Cox and Deacon John W. Foley.