Opposite the Cathedral is the Church of Ireland which dates back to the 17th Century. It would appear likely that when the ancient building at Conwall fell into ruins the first church was erected in Letterkenny.

The Civil Survey of 1652 -56 gives us an interesting picture in a few lines about the place in those days and testifies that there was a church in the town then. "There is a town

called Letterkenny which hath a market every Friday and two fairs in the year with a fair Church and a bridge at the east end over the River Swilly" - i.e. the Port Bridge. Canon J. B. Leslie says that in 1729 the Church was in good repair and that in 1733 it was slated and one side seated. These alterations took place while the Rev. William Spann was in Letterkenny - a Rector who did much for their parish. The beautiful Chalice and Paten still in use and dated 1744 were given by Dr. Spann, He died in 1752 and is buried under the Church.

Referring to Rectors of the past the name Joseph Stopford will be of interest as he was Grandfather of Stopford Brooke - the post literary critic and scholar who translated the Austrian Carol  "Stille Nacht", into words known worldwide as "Silent Night, Holy Night".

A large flat stone opposite the vestry door marks the early remains Rapparee Redmond O' Hanlon, the name and coat of arms are still distinct.

A Stone on the North Side commemorates Lord George Hill who recognised his college acquaintance, Wolf Tone after his arrest.. An obelisk at the East end is to the memory of Rev. Dr. John Kinnear a well known Presbyterian Minister in Letterkenny who was M.P. for the county of Donegal 1810 - 1886.