The graveyard adjacent to Iona Abbey, Reilig Oran is named after Odhráin or Oran who was one of St. Columba's followers. This burial ground has been in use since the saint's time and became the traditional burial place for the Kings of Dalriada and Scotland, for many centuries.

It is reputed to be the burial ground for 48 Dalriadan and Scottish kings, including Macbeth of Shakespearean fame, as well as eight Norwegian and four Irish kings. The Lords of the Isles were also buried here in the 13th, 14th and 15th centuries. The graves include the final resting place of John Smith, the former Labour Party leader, who loved Iona. His grave is marked with the epitaph: "An honest man's the noblest work of God". Many of the gravestones have been moved inside Iona Abbey's museum to protect them from the weather.

St. Oran's Chapel is a beautiful simple building with a striking Norman doorway. It is thought to be the oldest building on Iona probably dating from the 11th century.

It is said that Columba was prevented from completing the building of the original chapel until a living person had been buried in the foundations. His friend and disciple Oran volunteered and was duly buried. Columba later asked for the face to be uncovered so that he could bid a final farewell to his friend, but Oran was found to be alive and claimed he had seen Heaven and Hell, describing them in such blasphemous terms that Columba ordered he be covered up immediately.