Notwithstanding its very English appearance Cummins is a Gaelic Irish surname quite distinct from the English Cummings and Cumming, though sometimes the original O Coimin takes those forms as its anglicized synonyms. Indeed the number of variants in English is considerable - Commons, Comyns, Kimmons, commane and even MacSkimmins are recorded by the Registrar-General as being used as interchangeable with Cummins. O Coimin is first found in Connacht: the family were erenaghs of the church of St. Cuimin Fada, and the parish of Kilcummin on the western side of the Bay of Killala is named after them. The form Commons is now the most usual in Co. Mayo. It is a name about which much confusion is inevitable. It appears as O Comain in Munster, whence come the majority of present day Cumminses (also called Commane) now found in Counties, Tipperary and Cork. There they are sometimes called Hurley, through a mistranslation, caman being the Gaelic word for a hurley-stick. In some parts of Ulster the form in Irish is Mac Coimin, which is of long standing, for a deed relating to land in Co. Armagh, dated 1264, contains the name of Patrick MacCumyn. To add to the complexity the name Comyn, an Anglo-Norman, was Archbishop of Dublin from 1182-1213.

In one form or another the name appears in the roll of distinguished Irishmen from a very early date. In the sixth century, long before the introduction of surnames, St. Common, pupil of St. Finian, went from Ulster as missionary to Connacht and founded Roscommon and other monasteries in that province. Cormac O Cuimin, or Comon (1703-1786), was one of the many blind bards and shanachies of the eighteenth century. Another famous poet of that era was Michael Comyn (1688-1760), of Kilcorcoran, Co. Clare. His son Michael Comyn (b. 1704), emigrated to France where he was accepted as one of the nobility of France (descendants of Wild Geese of the name we were also enrolled amoung the nobility of Spain) and his grandson, John Frances Comyn (1742-1793), was guillotined as an aristocrat during the French Revolution, while David Comyn (1853-1907), another Clareman, was particularly active in the movements which led up to the formation of the Gaelic League. Some families of Comyn came to North Clare as papists transplanted under the Cromwellian regime from east of the Shannon, but the Inquisitions of earlier in the seventeenth century provide that families of the name were already well established in the county before that period. William Cumming (1769-1852), famous as a portrait-painter, was an Irishman who lived and worked in Ireland.