County Mayo is rich in history and archaeology and it has a rich archaeological heritage dating from prehistoric times to the present. According to the present state of archaeological knowledge, the first people arrived in Ireland sometime before 7000 BC during what is called the Mesolithic period. They were nomadic tribes of hunters and fishing people who built no permanent structures such as houses or tombs. The first colonisation of Mayo probably took place during that period.
There is a wealth of archaeological remains in Mayo with evidence of human habitation going back 5000 years. Many of these are relatively undisturbed and can be viewed at ease. Some of them are very famous, others less, but all are very interesting.
In County Mayo the most important archaeological site is Ceide Fields near Ballycastle. They are the oldest known field systems in the world, over five and a half millennia old. It is a unique Neolithic landscape of world importance, which has changed our perception of our Stone Age ancestors. The remains of stone field walls, houses and megalithic tombs are preserved beneath a blanket of peat over several square miles. They tell a story of the everyday lives of a farming people, their organized society, their highly developed spiritual beliefs, and their struggle against a changing environment beyond their control.
The town of Louisburgh counts over 700 known archaeological monuments, and 20 areas of scientific interest. There are court-tombs at Furmoyle and Aillemore, a megalithic wedge-tomb at Srahwee, abbeys at Kilgeever and Murrisk, a clapperbridge (stone bridge with 37 arches) at Killeen, and numerous other monuments, especially around Killadoon (Cill an Dúin, "church of the fort"). In Killeen graveyard, there is a large standing stone, christianised during the 7th century with a Maltese Cross, enclosed by a double circle. There is also an early Christian slab, inscribed with a main cross at the centre surrounded by four smaller crosses. This type of cross is known as the Cross of the Thieves.
Moytura Cong is the ancient site of a great battle, it abounds in cairns and other stone monuments. Studies of these stones indicate that they were erected over a long period of time, possibly from the Neolithic to the Iron Age and later and not as we may wish to believe, related to one event. Another remarkable feature of the Moytura Monuments are the stone circles. The circles, which display very different morphology, stand on the crest of a rise at distances varying between 89-177m from each other. Antiquarians have found it difficult to form an opinion as to what the function of these structures were in ancient civilisation, some believe they were defensive forts and others that they were druidic altars.
There are nine monuments in total, which include several stone circles and cairns, a megalithic structure and a large platform, all of these bare testimony to considerable Bronze Age activity in a limited area of twenty-three acres.
Kilcashel's archaeological site is rich in history and archaeology with many notable features in the Kilmovee area. There are 7 'Caiseals', including the largest 'Caiseal' in Connaught, at the rear of the present day Kilmovee football pitch. 'Caiseal' (pronounced Cash'l) is Gaelic for 'circular stone fort', and emanates from early Celtic history.
An Ogham Stone found in a wall in Kilmovee is mounted beside 'The Three Wells' - which are reputed to have sprung up when St Mobhi struck the ground with his staff when he had no water to baptise the local people.
The Dolmen of the Four Maols is located at the back of Ballina's Railway Station. The Dolmen dates from about 2,000 B.C. and is sometimes called locally the 'Table of the Giants'. The Dolmen is said to be the burial place of the four Maols. The four Maols murdered Ceallach, a 7th century Bishop of Connacht and were hung at Ardnaree - the Hill of Executions. Tradition says that their bodies were buried under the Dolmen.