¹Hobson, Mary. "Some Ulster Souterrains." The Journal of the Royal Anthropological Institute of Great Britain and Ireland 39 January-June (1909): 226-27.

²The souterrain at Donaghmore, just outside Dundalk, is also accessible. It is listed as a National Monument, although it is on private property. Visitors must provide their own lights. It has been described as, "...an elaborate dry-stone structure with traps, a secret passage and vents, built into a trench dug into boulder clay and, in places, into the underlying Silurian grit. The passages and terminal chamber total some 80 metres long, and they are both corbelled and lintelled."
According to Nancy Edwards, there are "upwards of 1,000 examples" of souterrains in Ireland. (Edwards, Nancy. The Archaeology of Early Medieval Ireland. Philadelphia: University of Pennsylvania, 1990. 29.)

³Hobson 220.

⁴MacDonogh, Steve. The Dingle Peninsula. Dingle, Co. Kerry, Ireland: Brandon, 2000. 50-51.
In one souterrain what appeared to be a ventilation shaft may have had an additional purpose. Mary Hobson writes, "At Tavenahoney in Glenan I found the only vent or shaft I have seen, though I know of another. I am not sure that it was intended for ventilation, but rather incline to the idea that it is a speaking tube to give warning to those inside; a boy spoke to me through it. It was closed on the outside by a rough stone like thousands scattered over the hillside." (Hobson, Mary. "Some Ulster Souterrains." The Journal of the Royal Anthropological Institute of Great Britain and Ireland 39 January-June (1909): 223.)
According to NUI Galway Archaeologist Michelle Comber, the evidence suggests that "souterrains served at least two functions - refuge and storage. Features such as constricted passages, chambers on different levels, settings for internal gates or doors were clearly designed to prevent quick/easy access to some souterrains. In addition, some have exits, facilitating underground movement from one place to another (though not over huge distances as many local tales might suggest!). Excavation, however, has also shown that some souterrains, at least, were also used for storage. Their cool interiors were ideal for storing foodstuffs, and the remains of timber barrels have been found." (Comber, Michelle. "Other Purposes of Souterrains." Message to the author. 27 Feb. 2012. E-mail.)

⁵"Binder's Cove Souterrain (Finnis Souterrain)." Banbridge District Council, Oct. 2008. Web. 24 Feb. 2012. <http://www.banbridge.com/uploads/docs/FinnisSouterrain.pdf>.
A geophysical survey of the area surrounding the souterrain, commissioned by the Council, reported, "... an unusually large number of archaeological features including....a large enclosure complex, or a series of succeeding complexes, to the western side of the survey area appearing to be associated with at least one substantial stone structure, of medieval or post-medieval origin. In the north, the souterrain appears to dominate the landscape with all adjacent archaeological features respecting its limits, with the added possibility of a trackway leading to it. In the east another potential enclosure was identified."

⁶Souterrains are often referred to as "caves." The Irish word for cave is uaimh, pronounced "oo-ov." Conflating uaimh with "cave" results in "cove." (http://www.irishmegaliths.org.uk/down.htm)

⁷"Binder's Cove: Your Place and Mine." BBC News. BBC, May 2008. Web. 24 Feb. 2012. <http://www.bbc.co.uk/northernireland/yourplaceandmine/down/A1956017.shtml>.
The local person who first suggested making the souterrain accessible to the public, Oliver Quail, was also the stonemason who worked on the structure's restoration prior to its opening. During the winter months when the tunnels are flooded and the gate is locked, the key may be obtained from O'Hare's garage on the B7 Rathfriland Road, near the local settlement of Finnis/Massford (2004 information).

⁸Macrory, J.M. "Souterrain at Leitrim, Parish of Drumgooland." Ulster Journal of Archaeology Second 12.2 (1907): 70-72.
"This region of South Down, once part of the princely patrimony of the Magennis family, so far as the antiquary is concerned, is almost an untrodden field. Here abound rath and dun, cromleac and cistvaen, sculptured Celtic cross and pillar stone, cashel and crannog, ruined castle and carn, souterrain and ancient burying-place-objects which fire the imagination and gladden the heart of the archaeologist, arousing inspiration for a dreaming of the 'dim and dateless past.' Here, amongst a people most obliging and courteous in manner, the belief in the power of blessings and maledictions, in apparitions and banshees, in fairies and witches, in myths and dreams, in spectres and spells, in charms and elf-shooting, and in good and bad luck, still obtains to a greater or less extent. Old faiths and customs or usages die hard in a community which has had an unlimited stock of wonderful traditions, handed down from generation to generation, from the far-off past, whose imagination pictures even natural occurrences, if at all out of the range of comprehension, as the work of some direct supernatural agency. The lover of things and ways of other days must in a large measure regret the passing of that indescribable charm associated with the folk-lore of a highly imaginative, interesting, and romantic people."

⁹Emerson, John. "Passage Connects to Fort." Personal interview. 30 June 1979.

¹⁰O'Looney, Brian. "On Ancient Historic Tales in the Irish Language (XXXVI)." Proceedings of the Royal Irish Academy Polite Literature and Antiquities 1 (1879): 222-23.
The souterrain at Rathcroghan is also known as the "Cave of the Cats," or "Ireland's Hell-Gate." In "The Cave of Ainged," after Nera entered the cave he was taken prisoner by the fairies, put to work, and compelled to marry one of their women. He finally managed to escape, and returned to the king with much information regarding the cave and its contents, enabling the army to break into the treasure house of the sídh and carry off great treasure. This tale may be read in its entirety here.

¹¹Hobson 226-27.