The first St Cornelius, or St Constantine, as it was also called in its early days, was a small log church built on this site in 1834 on a four-acre tract of land donated by Cornelius Murphy. Cornelius Murphy was a very enterprising man who emigrated in 1818 from County Cavan, Ireland. Murphy established a store and hotel on his crown grant in Caledon Township. Unfortunately, Cornelius Murphy was one of the earliest interments in St Cornelius churchyard, having died in 1836. This small log church was soon outsized by the growing community around Silver Creek, or Caldwell as it was officially called. In 1847, this original log church was replaced with a 36' x 48' (10m x 14.6m) frame church. This church had a spire and was roughcast on its exterior. In its early days, St Cornelius was a mission of St Patrick's in Toronto Gore Township, with a mission priest coming from St Patrick's every fortnight to serve the parish. In 1867 Caledon became a parish on its own, with the church in Albion Township (St Alphonsus) a mission. In 1886 the parish replaced the frame church with the present-day brick church. With the construction of a new Church in Albion in 1901, St John the Evangelist and a new rectory in 1908, the priest left St Cornelius and relocated to St John's in Albion. The population of Caledon Township had fallen dramatically by the early 20th century. Thus the parishes reversed their roles, with St Cornelius becoming a mission of Albion. In 1915 St Cornelius became a mission of Orangeville. This arrangement lasted until 1981 when St Cornelius again became a mission of St John's in Albion.

This churchyard is the resting place of many of Caledon's pioneers.