The McMenamins (meaning 'son of Meanma', courage, high-spirits) were a warrior branch of the O'Donnells of Tirconnell (Donegal), who were the "chieftains of Fanad" a large territory in Donegal.

After a dynastic feud between two of the ruling O'Donnell line - the Lector O'Donnell grandsons Aodh (Hugh) and Donnchadh (Donogh) were slain in 1303. But Lector was an important church office - one mentioned constantly in the Annals - and it seems clear that the Lector O'Donnell's descendants (the McMenmin’s) found their future in the Irish church. They probably turned to the church because the real political power in Donegal was in the hands of their cousins, the O'Donnells, and their home territory of Fanad was soon taken over by the MacSweeneys, a galloglaghs (gallowglasses) sept from Scotland (employed as mercenery soldiers), who served the O'Donnell Kings.

The McMenamin’s seem to have originated in Donegal at least as early as the 13th Century in which the first members Aodh (Hugh) and Donnchadh (Donogh) MacMenamin, were both slain in 1303.
Over the centuries, some migrated eastward into what is now know as Northern Ireland where the name often changed to a "y"-ending. Some of these later migrated to Scotland and, in the last century or two, some migrated back to Ireland! There are still quite a number in Scotland, particularly around Glasgow.

This surname McMenamin which originated in Co. Donegal is still found there and in west Tyrone.

There was considerable migration to Mayo in the early seventeenth century, following the defeat of Ulster by the English and "The Flight of the Earls," and this accounts for the presence of the surname in that county today.

A great number of variations stemmed from the name McMenamin. When English colonising or census officials or American immigration officials recorded the name they heard from an Irishman who had a thick brogue and often couldn't write, many variations developed. So names such as McMenomey, McMenemy, McMenamy, McMenomy, McMenomay, MacMenomay, McManemy, McManamay, McMenomin, McManomon, McManmon, McManiman, McManman, McMenamon, McMenimen, all began as McMenamin!

Evidence points to that the McMenamin's might have originated in Donaghmore Parish and the area around it and according to history (or legend - often interchangeable), Donaghmore Parish and it's chapel at the "Cross-roads," just below Killygordon, was personally founded by St. Patrick. The current St. Patrick's Church now supposedly stands on the site of the first chapel. Donaghmore Parish and the church could then have been a focal point for people in the area.

One record keeper (a priest for some parish records I think) listed the meaning of our name. Something like: Keeper of the Castle key, Castle guard, or Castle watch. This record keeper also said they were of royalty or wealthy at one time with a great deal of land and that the British had confiscated their land and
sent them to live in the bog lands of Donegal.

"I had heard that at one time the McMenamin’s had been wealthy with a great deal of land and that the British had confiscated their land and sent them to live in the bog lands of Donegal.

So it is at least possible that the McMenamin’s had been historically the Keepers of O'Donnell's castle in Donegal Town. The O'Donnells had an older castle at Ballyshannon, but this was abandoned when they built their new, larger castle at Donegal Town in the late 1400's. And the late 1400's is precisely the time when the MacMeanman O'Donnells disappear from the Papal Letters.

The parishes listed all lie in a straight line, running east-west from Inishkeel at the west end to the east end with Donaghmore and in Co. Tyrone, Termonamongan. Running through them all except an outlier like Conwal, again on a west-east line, are the River Finn, and along side it the Glenfin Road and a railroad, dismantled some time in the past. This area has been historically known as the Glenfin (Valley of the Finn). The Glenfin Road is not imposing but has long been the main road through the area. The railroad was important once but I don't know when it began to operate and when it was closed. In any event, these parishes had a set of common transportation routes linking them.

More on The Flight of the Earls: "1601...Hugh O'Neill, Catholic Earl of Tyrone, backed by Spanish troops, attempts to halt English conquest of Ulster, but is defeated at the battle of Kinsale, near Cork. 1607...O'Neill and his ally, Rory O'Donnell, the Earl of Tyrconnell - along with many Ulster chieftains - escape to the Continent [and some to Mayo - see above] in the so-called Flight of the Earls. Their lands are taken over by the English and Scottish settlers, who begin to turn Ulster into a bastion of Protestantism." - from "Dublin," by Brendan Lehane, contributed by Patricia (McManiman) Orstad.