St. Mura's Cross and Slab - Fahan Fahan is the site of the ancient Abbey of St. Mura. Founded in the early 7th century, it had been used for religious activities for over 1000 years. The cross-slab is in the middle of an old graveyard. A cross is carved on both sides of the slab in the form of a Latin Cross, which has a long stem giving the appearance of a Greek Cross. The Cross on each side consists of a broad interlaced ribbon. The West face of the Cross has a more elaborate design and two figures can be seen on either side. They are said to be ecclesiastics. Both have long hair and wear long garments on which inscriptions have been written. It has not been possible to decipher them.

Located in the walls of the graveyard are two artefacts associated with the old abbey, an inscribed Greek cross and a stone thought to be a holy water font.

This early monastic site was a Columban foundation of the 6th century A.D. Its first abbot was St. Mura, to whom the decorated cross-slab (dated to 7th-9th century) is dedicated. He was a patron of the O'Neill's and died in 645 A.D. to be succeeded as abbot Callach. Many of the original treasures of this abbey were removed, the shrine of St. Mura's Bell (a highly ornate work of gold, silver and precious stones) and Bacal Mura (Mura's Crozier) are now to be found in the Wallace collection of the British Museum and the National Museum, Dublin respectively. Other items are in Scandinavia, but luckily the original holy water font is in Inishowen in the Catholic Church at Lagg. It was said that the O'Neill's did not swear on the Bible but on Bacal Mura. The church was burned in 1101 according to the Annals of the Four Masters.

The importance of this site is evidenced by the fact that the abbot of the time, Fothadh na Canona, was visited by the High King of Ireland, Aedh Oirnie, regarding a complaint from the religious that they were compelled to military service. Aedh Oirnie said he would abide by Fothadh na Canona's decision on the matter, which was to release the religious from that duty. Other abbots included Maol Mura, who died in 884 A.D. He was a poet famous for his historical poems including one example on the history of the Phoenicians. The erenaghs (laymen who took care of the material concerns of the monastery) to the monastery traditionally came from a local family called Hegarty. Erenaghs continued to be associated with Fahan until the early seventeenth century.

The present ruins in the graveyard probably date to the seventeenth century. A Royal Commission report from 1622 reported that the parish church was in good repair. It continued in use until 1820 when the new church was built a short distance away. Lacy believes that the blocked rectangular window in the South wall of the church ruins is probably of an earlier date.

Return to the main road and carry on to Buncrana. From here take the road to Clonmany/Ballyliffin. About 1½ mile from Ballyliffin on the Carndonagh road, turn left at signpost for Isle of Doagh. Continue on this road to the extreme tip of the Isle of Doagh to Carrickabraghy Castle. The castle is clearly visible from the road.