The core structures of the church, including the west tower and chancel, are dated to the 15th century.

[2] These include a residential tower, attached to the church, in which the priest lived.

[citation needed] Other structures of the church date from redevelopments and expansion works in the late 18th century.

[citation needed] The Roman Catholic church in Newcastle, also dedicated to Saint Finian, was built in 1813.

[3] Both churches, Catholic and Episcopalian, are included on the Record of Protected Structures by South Dublin County Council.