The Presbyterian presence was felt in St. Marys as early as the beginning of the 1840’s. The first gathering places for worship were homes, shops and schools, but as numbers and strength increased, so did the need for larger quarters. The congregation’s dream of a building of its own became closer to reality with James Ingersoll’s gift in 1849 of a piece of property. The lot was occupied within three years by the first church building. At least two subsequent additions were required to allow for the growing congregation and by 1873 a campaign was underway to solicit funds for a larger and more appropriate structure. The existing building was built after the split of First and Knox congregations. After three years and $16,000. the first service of worship was held in the "First" Church building on March 20, 1881. After two attempts at union, a permanent resolution was passed and the congregations met for worship at Knox until 1964 when they returned here which is today the home of Presbyterians in St. Marys.

On Sunday, November 20th, 1988, the church’s massive 25 ft. west chimney collapsed, smashing through the roof and sanctuary coming to rest in the basement. Worship was held for ten months in the neighbouring Arthur Meighen Public School. The congregation grew both in number and spirit as the $206,000.00 rebuilding project neared completion. September 10th of the following year marked the re-dedication of St. Marys Presbyterian Church. In 1993 a two storey east wing was completed along with a sanctuary balcony providing seating for over one hundred worshippers. At a cost of just over half a million dollars (raised and paid off in only three years), the new facilities added nursery, office, library, music, church school and meeting room space, further enabling the congregation’s continued growth both in numbers and community ministry.

Roof and steeple repairs were done in 2002 and 2003 for a total of $550,000.00. The second phase of repairs is planned in 6 to 10 years for a total of 1.2 million.  The pledge commitment concept was used again for this project, but with a different angle.  The money raised will go into an Enduring Mission Fund which will support the church for years to come.

Today, St. Marys Presbyterian Church is a congregation active in Worship and in the practice of a compassionate mission program at local, regional and international levels, fulfilling 162 years of faithful service and witness to the redeeming love of Jesus Christ.