St. Mary Church was established as a community of the faithful in 1832. It is the oldest Catholic parish in New Haven and the second oldest in Connecticut.

 

Land was purchased near the intersection of York Street and Milford Turnpike Road in New Haven. In 1834 a church was completed on this site and given the name "Christ's Church." In 1848, the Church was destroyed by fire. Several months after the fire, the property occupied by the Church Street Congregation Society was made available. Plans for the church were launched in 1851. Over the next 20 years this ambitious and impressive edifice developed, designed by James Murphy—at a time when the city's Catholic population was steadily increasing. Built on New Haven's finest residential street, Hillhouse Avenue, St. Mary's represented the faith, the pride, and the high hopes of New Haven's struggling Catholic families.

The church was dedicated in 1874, celebrated for its beauty but burdened financially. History of New Haven County, Connecticut, 1892 wrote of St. Mary Church, "It is a fit evidence of the vigor and zeal of the congregation which occupies it." The original plans for a steeple were dropped and the façade of St. Mary's for more than a century featured an untopped stone tower without belfry or spire. Still, the church was from the first a remarkably handsome, forthright, and lasting symbol of Roman Catholic devotion in the city. In 1982, in recognition of the 100th Anniversary of the Knights of Columbus, the church went through a complete renovation. Although included in Murphy's original plans, the spire was never completed. The installation of the spire was part of the renovations, courtesy of the Knights of Columbus. Rising 179 feet from the once-stubby tower of the church, the neo-Gothic spire is among New Haven's highest structures. 

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Under the energetic administration of the Dominican order since 1886, it remained a thriving primary Catholic presence in downtown New Haven. St. Mary Church is recognized as a shrine and birthplace of the Knights of Columbus.

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St. Mary Church underwent massive historic preservation and artistic renovation from February 2019 to September 2020 under the guidance of Pastor John Paul Walker, OP.

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In 2021, St. Mary’s was chosen to be the center of a new archdiocesan plan “because it is perfectly situated to be the geographical and spiritual focal point of a municipal model for New Haven.” The Archdiocesan plan for St. Mary’s called for diocesan priests to serve at St. Mary’s and the nine other churches in New Haven. The friars gifted the parish with a triduum of Masses in November, during which the whole parish family prayed together for the coming transition. Since December 1, 2021, our faithful diococean fathers have led our dynamic parish with fatherly guidance and spiritual assurance in this new era as a New Haven Catholic parish.