This unusual surname is of early medieval Scottish origin, and is a locational name from the lands of Carruth, west of the Bridge of Weir in Renfrewshire. The component elements of the placename are the British (pre Roman) "ker", fort, reflected in the Welsh "caer", fortress, with the Celtic "ruadh", reddish, used here either as a personal byname for one of ruddy complexion, or as an adjective reflecting the colour of the earthworks. The ancient parish of Carruthers in Annandale, Dumfriesshire, shows the same initial element with a compound personal name meaning "Red Ruler" as its second. Locational names, such as this, were originally given to local landowners, and the lord of the manor, and especially as a means of identification to those who left their birthplace to settle elsewhere. One of the earliest recordings of the surname in London was the christening of John Caruith, an infant, at St. Martin in the Fields, Westminster, on April 28th 1619. It is widely recorded in Renfrewshire Church Registers from the mid 17th Century under the variant spellings: Caruth, Carruth, Corruth and Curruth. On November 24th 1656, John Carruth and Jean Houstoun were married in Kilbarchan, Renfrew, and in 1686, Jean Carruth, noted in the "Register of the Privy Council of Scotland" was charged with "attending conventicles in Dalry". The first recorded spelling of the family name is shown to be that of Alexander Corruith, which was dated 1575, witness in "Records of Renfrewshire", Scotland, during the reign of King James V1 of Scotland, 1567 - 1625. 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.