On Friday, June 19, 1959, a provincial plaque was unveiled on the grounds of the church at 99 Hunter Street in Peterborough. The plaque reads:
ST. JOHN'S CHURCH 1834
An Anglican congregation was formed in Peterborough by the Rev. Samuel Armour in 1826. Services were held in a schoolhouse until the building of St. John's was begun in 1834 and opened in the summer of 1836. Designed by Joseph Scobell and assisted by financial contributions from England and Ireland, it is a fine example of Early English Gothic Revival architecture. In 1882 it was extensively renovated. The first rector was the Rev. R.H. D'Olier, a native of Dublin, Ireland, who served until 1837. St. John's is the oldest remaining church in Peterborough County and has been in continuous use since its opening.