County Town is Sligo
County Library, The Courthouse, Sligo
County Sligo Heritage and Genealogy Centre, Aras Reddan, Temple Street, Sligo City
Registrar General Northwestern Health Board, Markeviecz House, Sligo
(This Connaught county contains the towns of Sligo, Ballymote, Collooney, Ballysodare, and Enniscrone.)
Sligo was the ancestral territory of a branch of the O'Connors, called O'Connor Sligo. Other Gaelic families associated with the county include O'Dowd, O'Hara, O'Hart, McDonagh, Mac Firbis, and O'Colman. The site of the town of Sligo has been of strategic importance since ancient times as all traffic on the coastal route between South and North had to ford the river here. A fortress which guarded this ford was plundered by Norse pirates as early as A.D. 807.
After the Norman invasion of Connacht in 1235, Sligo was granted to Maurice Fitzgerald who effectively founded Sligo town by building a castle there in 1245 and making it his residence. The Taaffe family was among the Norman families who settled in the county. Further settlers were brought into the county at various periods, including weavers from the north of Ireland brought in by Lord Shelbourne in 1749.
As the native Irish and Norman population were predominantly Catholic, the Scottish usually Presbyterian, and the English of the Protestant faith, the proportions of these religions among the population can, in very general terms, be used to estimate the origins of the inhabitants of the county. When religious affiliation was first determined in the census of 1861, the respective proportions of Catholic, Presbyterian, and Protestant in Sligo were 90, 8, and 1 percent. Apart from the weaving industry and some mining operations, Sligo is basically an agricultural county. The town of Sligo was an important port in the eighteenth and nineteenth centuries, particularly as the River Erne and its lake systems facilitated inland trading and transport. It was also an important port of emigration. The peak of population was reached in 1841 at 181,000. The Great Famine of 1845-47 badly affected the county and the population had dropped by 52,000 in ten years, including some 20,000 deaths. By 1901 the population had fallen to 84,000 and is currently 56,000.