It is bounded on the north and west by the Atlantic Ocean; on the south by County Galway; on the east by County Roscommon; and on the northeast by County Sligo. Mayo is the third-largest of Ireland’s 32 counties in area and 18th largest in terms of population. It is the second-largest of Connacht‘s five counties in both size and population. Mayo has 1,168 km (726 mi) of coastline, or approximately 21% of the total coastline of the State. It is one of three counties which claims to have the longest coastline in Ireland, alongside Cork and Donegal. There is a distinct geological difference between the west and the east of the county. The west consists largely of poor subsoils and is covered with large areas of extensive Atlantic blanket bog, whereas the east is largely a limestone landscape. Agricultural land is therefore more productive in the east than in the west.
The highest point in Mayo (and Connacht) is Mweelrea, at 814 m (2,671 ft)
Ireland’s largest island, Achill Island, lies off Mayo’s west coast
Mayo has Ireland’s highest cliffs at Croaghaun, Achill Island, while the Benwee Head cliffs in KilcommonErris drop almost perpendicularly 270 m (900 ft) into the Atlantic Ocean.
The northwest areas of County Mayo have some of the best renewable energy resources in Europe, if not the world, in terms of wind resources, ocean wave, tidal and hydroelectric resources.
During the early years of the 19th century, famine was a common occurrence, particularly where population pressure was a problem. The population of Ireland grew to over eight million people prior to the Irish Famine (or Great Famine) of 1845–47. The Irish people depended on the potato crop for their sustenance. Disaster struck in August 1845, when a killer fungus (later diagnosed as Phytophthora infestans) started to destroy the potato crop. When widespread famine struck, about a million people died and a further million left the country. People died in the fields of starvation and disease. The catastrophe was particularly bad in County Mayo, where nearly ninety per cent of the population depended on the potato as their staple food. By 1848, Mayo was a county of total misery and despair, with any attempts at alleviating measures in complete disarray. There are numerous reminders of the Great Famine to be seen on the Mayo landscape: workhouse sites, famine graves, sites of soup kitchens, deserted homes and villages and even traces of undug ‘lazy-beds’ in fields on the sides of hills. Many roads and lanes were built as famine relief measures. There were nine workhouses in the county: Ballina, Ballinrobe, Belmullet, Castlebar, Claremorris, Killala, Newport, Swinford and Westport.
A small poverty-stricken place called Knock, County Mayo, made headlines when it was announced that an apparition of the Blessed Virgin Mary, St. Joseph and St. John had taken place there on 21 August 1879, witnessed by fifteen local people.
A national movement was initiated in County Mayo during 1879 by Michael Davitt, James Daly, and others, which brought about a major social change in Ireland. Michael Davitt, a labourer whose family had moved to England joined forces with Charles Stewart Parnell to win back the land for the people from the landlords and stop evictions for non-payment of rents. The organisation became known as the Irish National Land League, and its struggle to win rights for poor farmers in Ireland was known as the Land War. It was in this era of agrarian unrest that a new verb was introduced to the English language by Mayo – “to boycott“. Charles Boycott was an English landlord deeply unpopular with his tenants. When Charles Steward Parnell made a speech in Ennis, County Clare, urging nonviolent resistance against landlords, his tactics were enthusiastically taken in Mayo against Boycott. The entire Catholic community around Lough Mask in South Mayo where Boycott had his estate became a campaign of total social ostracisation against Boycott, a tactic that would one day come to bear his name. The campaign against Boycott became a cause célèbre in the British press after he wrote a letter to The Times. The British elite rallied to his cause and Fifty Orangemen from County Cavan and County Monaghan travelled to his estate to harvest the crops, while a regiment of the 19th Royal Hussars and more than 1,000 men of the Royal Irish Constabulary were deployed to protect the harvesters. However, the cost of doing this was completely uneconomic: It cost the British government somewhere in the region of £10,000 to simply harvest £500 worth of crops. Boycott sold off the estate and the British government’s resolve to try to break boycotts in this completely dissolved, resulting in victory for the tenants. The “Land Question” was gradually resolved by a scheme of state-aided land purchase schemes. The tenants became the owners of their lands under the newly set-up Land Commission.
A Mayo nun, Mother Agnes Morrogh-Bernard, set up the Foxford Woollen Mill in 1892. She made Foxford synonymous throughout the world with high-quality tweeds, rugs and blankets.