This interesting and unusual surname has two distinct possible sources, each with its own history and derivation. Firstly, McRill may be of early medieval Scottish origin, and an Anglicized form of the Old Gaelic "MacFheargal", son of Fearghal, an ancient male given name composed of the elements "fear", man, and "gal", valour, ardour. The surname is now more usually Anglicized as "Mackerral" and "Mackerrel". Early bearers of the name include: Radulfus Makerel, charter witness in Roxburgh, circa 1200; Sir John M'Kirel, who distinguished himself at the battle of Otterburne in 1388; and William McKeirell, sheriff of Ayr in 1595. Surnames derived from given names are the oldest and most pervasive surname type, and in vernacular naming traditions (as distinct from religious), names were originally composed of vocabulary elements of the local language, and no doubt bestowed for their auspicious connotations. The second possibility is that McRill is of early medieval English origin, derived from the Middle English and Old French "makeral", mackerel, originally given either as a metonymic occupational name to a mackerel fisherman, or as a nickname to someone thought to bear a fancied resemblance to the fish. One William Makerell (Lincolnshire, 1273) is the earliest recorded namebearer from this source, and the form "McRill" shows an altering of "Mack(e)rell" by folk etymology as if of Gaelic origin. The first recorded spelling of the family name is shown to be that of Recherus Mecmaccharil, who witnessed a charter by Dunekan, Earl of Karic, which was dated circa 1165, in "Early Medieval Records of Melrose", during the reign of King William "The Lion" of Scotland, 1165 - 1214. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.