[from Manx Place-names, 1925]
GLENFABA is bounded on the north by Michael, on the south by Rushen, on the east by Middle, and on the west by the sea. The ancient boundary of the sheading went from Lag ny killey on the west coast northwards to Glion Shellan, the northern boundary of the Treen of Scaresdale ; from thence to the western boundary of Stockfield, to Little London, then southwards through Glion ny Gill, through the Lhergy Ruy pass, over Greeba mountain, crossing the Dhoo Valley at Creg y Quilliam ; thence to Ardchallagan and Foxdale, over the northern ridge of South Barrule, over Cronk Fedjag, and Cronk yn Irree Laa to Lag ny killey. Kirk Marown is in the sheading of Glenfaba as now constituted. (v introduction to Garif).
We find the name regularly spelt Glanfaba or Glen-faba,  in our earliest records. In a Bull of Pope Gregory IX, 1231 , We find Terra de Glenfaba mentioned as belonging to the Bishopric of Mann.
The second element of this name is obscure, and it is probably one of our bed-rock names bequeathed to us by the non-Aryan race or races, which inhabited our islands before the coming of the Celts. Such names are found all over the British Islands, especially those applicable to mountains and rivers, and an attempt to solve their meanings is fruitless, for they defy analysis. One of these races was known to Ptolemy as the Ivernians; this was probably the people known in Irish myth and legend as the Fir boig or 'Bag-men', and authorities generally agree that these neolithic aboriginals spoke a non-Aryan tongue.
The name Glenfaba appears to have been originally applied to Glen Mooar and Glen Helen, which are drained by the river Neb In the 13th century the lands westward of the river here were held by the Bishops of Mann, but eventually became abbey lands.
In Faba and Neb we have probably the same name. Thus Feb being a feminine noun, as river-names usually are, became yn Eb (v. introduction p. xxi), and then Neb. in Faba we probably have a genitive form, i.e. the glen of the Fab or Feb. It thus appears clear that the element is a river-name, but with our present state of knowledge it is impossible to hazard a guess as to its interpretation.
The following Gaelic surnames found as component parts of place-names within this sheading, have been lost : O'Carnigan, O'Hassey, O'Murran, O'Neanan, O'Rody, O'Doyne, O'Dorgan and OHarra.
Eighteen Norse names still survive in the sheading, but none ofthern contain personal names. We find -byr (homestead) in Dalby and Rheaby and as a prefix in Beary. Stadr, of similar meaning, in Skerestal. Dair, (glen, dale), is found in Foxdale and Sandall (the latter obsolescent) and as a prefix in Dalby. Fjall (mountain, hill) in Masool, Lammal and Stockfield. A (water, river) in Threlja, Vile (creek, bay) in Lhiannag, and several others, including the well-known name Tynwald.
Besides the name of the sheading already discussed, the following cannot be satisfactorily dealt with, and may belong to the same class : Avil (in Lag Avil), Nathan, Tittan, Shoaner and Rougimany.