St John the Evangelist's Church at Crosscanonby is about half mile from the coast at Allonby bay, at one of the earliest Christian sites in Cumbria. The Roman road from Carlisle to Maryport passes nearby, and there is evidence in the fabric of the Norman church of stones that were used in a Roman building of some sort.

The present building dates from AD 1130, with the south aisle added in the 13th century.

There are two Victorian stained glass windows.

The church was established near the line of the Roman road which ran from the fort at Maryport to old Carlisle. It has long been assumed that the building stone for this fine old Norman church came from a Roman building near the road since so much Roman-marked masonry is to be found in the church fabric.     

What the building was is a matter for conjecture. It could have been a wayside halt for travellers, a signal station or look-out in the Solway chain of defences, or perhaps the residence of some Roman or Romano British leader who wanted a country house away form the bustle of the military quarters at Maryport.

 During a restoration of the church in 1880 a number of sculptured stones were found in the fabric of the building and ten years earlier the lower part of a Roman altar was found in the churchyard, an altar which had been dedicated by Acilianus, prefect of the 1st Cohort of the Dalmations. It is now in the Neherhall collection and is one of five dedicated by this same officer of the Maryport Garrison. The number of sculptured stones found during eh 1880 restoration makes one wonder how many other stones are still concealed in the church fabric, which would, if recovered, answer some of the questions about the antiquity of this religious site. The most interesting of these stones is the remarkable 'Lawrence' slab, so called because it has been assumed that the human figure on it represents St Lawrence who was martyred on a grid iron.