The original name of what is labelled on maps as ‘St Clement’s Chapel’ on North Uist was given as Kilchalma and Kilchalmag. The second of these is probably the ‘correct’ form. As such, it reflects one of many nickname-forms (called ‘hypocoristics’) of the name Columba, of which Calmag (earlier Colmóc), and Colmán are just two (Russell 2001). This does not mean that Kilchalmag on North Uist was dedicated to St Columba of Iona, and, indeed, that is unlikely. He is much more frequently found in the Hebrides in the form Colum Cille, as we do elsewhere in Uist. Because of that, it is likely that Kilchalmag is named from one of the many, many other saints named Colmán who lived in the early middle ages in the Gaelic world. Although some of these individual saints may in origin represent the same historical individual, it is clear that there were, for whatever reason, a great number of people operating in the early medieval Gaelic church named Colmán, and variants of that name (for a sense of this, Ó Riain 1985, 141-44 has a huge list). Sometimes there are other details (like the feast day of the local church, or a local fair day) that help us pinpoint which saint is in a place-name, but we are not in luck with this particular site. For an overview of all the dedications to saints with names like this, and a map of their activities, it is worth looking at the page for this cluster of saints on the Saints in Scottish Place-Names website.
Probably our best parallel to the problem is the name of Portmahomack, which in recent years has been revealed as a major early medieval monastery (Carver 2008). In this place-name, the name of the saint in question has a very similar form (Mo Cholmag, earlier Mo Cholmóc, ‘my little Colum’) to the name in Kilchalmag. So at a guess, Kilchalmag might commemorate the same saint as found in Portmahomack. The bad news is, of course, that we are in the same boat with Portmahomack, of not being entirely sure who is being commemorated. Here, however, an early source, from the 9th century, referring to a ‘Colmán of Moray, north of the Mounth’, commemorated on 18 February, likely alludes to him (DoSH), though it doesn’t get us that much further forward. A similar situation relates to a place on the island of Bute which shares a very similar name to our Kilchalmag: the now lost Kilmachalmaig (NS045672), which is extensively discussed by Gilbert Márkus (Márkus 2012, 395-7; also 110-16).
Perhaps the two most prominent contenders for the saint in North Uist’s Kilchalmag are St Colmán of Dromore, whose feast day was 7th June (because of which he has sometimes been thought identical with St Columba, whose feast day is 9th June), and who looks like he was associated with the monastery of Inchmahome in the Lake of Menteith (see McNiven 2014, 54-59; Herbert 2008); and Bishop Colmán of Lindisfarne, who famously left that monastery after he and his party lost the dispute over the dating of Easter at the Synod of Whitby (see MacQuarrie with Butter, 2012, 336-9). This Colmán’s eastern sphere of activity make him attractive as the saint lying behind Portmahomack, and, one would guess, this northerly cult of a saint whose name took much the same form as we have in Kilchalmag, makes him attractive for the saint in North Uist as well.
For North Uist, however, there are really just too many options. As noted under the discussion for St Clement, one Colmán Duibh Chulinn, possibly associated with Baltinglass in Co. Wicklow in Ireland, but certainly associated with Comgall of Bangor, shares a feast day with St Clement (24 November); perhaps that is a clue? But why the cult of such a saint would have found itself in North Uist would be difficult to say.
Perhaps the most important aspect of this dedication is the form of the saint’s name. These ‘hypocoristics’ are largely a product of the early phase of the evolution of the church in the Gaelic-speaking world. This seems one more place-name for a church which is easier to explain as having been created early (in the pre-Viking period) on rather than in the later medieval period of Gaelic resurgence.