Fermanagh is one of four counties of Northern Ireland to have a majority of its population from a Catholic background, according to the 2011 census.

[1] Fermanagh spans an area of 1,851 km2 (715 sq; mi), accounting for 13.2% of the landmass of Northern Ireland.

Extensive sandstone can be found in the eastern part of the county, laid down during the Devonian, 400 million years ago.

Much of the rest of the county's sediments are shale and limestone dating from the Carboniferous, 354 to 298 million years ago.

The carboniferous shale exists in several counties of northwest Ireland, an area known colloquially as the Lough Allen basin.

The basin is estimated to contain 9.4 trillion cubic metres of natural gas, equivalent to 1.5 billion barrels of oil.

The Menapii are the only known Celtic tribe specifically named on Ptolemy's 150 AD map of Ireland, where they located their first colony—Menapia—on the Leinster coast c. 216 BC.

They later settled around Lough Erne, becoming known as the Fir Manach, and giving their name to Fermanagh and Monaghan.

In the early 9th century, the Erne was considered to be the boundary of Connacht and Ulster, specifically the over-kingdom of Airgíalla.

The Fir Manach proper, Tirkennedy and Magherastephana, along with Clankelly were part of the western Airgíalla group-kingdom of Uí Creamthainn with its seat at Clogher, whereas Lurg was associated with the northern Airgíalla branch of Uí Fiachrach centred at Ardstraw.

However, on the confiscation of lands relating to Hugh Maguire, Fermanagh was divided in a similar manner to the other five escheated counties among Scottish and English undertakers and native Irish.

Fermanagh was made into a county by a statute of Elizabeth I, but it was not until the time of the Plantation of Ulster that it was finally brought under civil government.

This constituency elected Provisional IRA hunger-striker Bobby Sands as a member of parliament in the April 1981 Fermanagh and South Tyrone by-election, shortly before his death.