From the first Masses celebrated in Westfield sometime between 1828 and 1830, to our current parish family made up of over 2,700 families, St. Mary's has had a rich history. In 1853 the first St. Mary's was built. This wooden structure was quite simple. It was nearly burned to the ground on the eve of July 4th, 1854 by an unruly crowd led by the "Know Nothings". Thanks to some opportune words by town selectman Hiram Hull and the presence of the men of the parish the mob was diverted.

​St. Mary's became an official parish in 1862 with Fr. M. X. Carroll as her first resident pastor. To understand the scope of that first parish one need only realize that every other parish in Westfield as well as Our Lady of the Lake in Southwick had their origin in St. Mary's.

In March of 1881 the original wooden church burned down. The immediate cause of the fire was attributed to a faulty flue. This great tragedy inspired in the people an immediate response. They cleared the debris, excavated the land and by Christmas of 1881 they were celebrating Mass in the basement of the church that we currently use. The completed church was dedicated on March 1, 1885.

St. Mary's has gone through many renovations and improvements over the years. Remember that the brick church as it was built did not even have bathrooms. Things like the elevator and air conditioning were also added. In March of 2008, a three year process of renovating the church was completed. Safe egress was improved with the addition of a new stairwell. Handicapped accessibility and easier circulation was addressed by relocating the steps into the sanctuary. Every painted surface was cleaned and re-painted. The floors and pews were refinished. The lighting and sound system was totally overhauled. Maybe most impressively, an 1897 Casavant Organ (Opus 78) was installed in the choir loft. It is the oldest Casavant organ still in use in the United States.

Today, St. Mary's is a thriving parish with many active parish groups ranging from Cub Scouts to the Confraternity of the Most Holy Rosary, from Knights of Columbus to the High School Pro-Life Club. We have been providing quality Catholic Education since 1898.  St. Mary's Parish School educates students in Pre-School through Grade 8. Our Religious Education program runs from Little Church for children as young as 4 years old, to Bible Study and presentations for our adults. Our rich history continues to grow with each passing day, under our patroness, St. Mary, in service to our loving God.