McGraw surname is an Anglicized form of the Old Gaelic "Mac Craith", the earlier form of which was "Mac Raith", composed of the elements "Mac" meaning son of plus "Rath" an old byname meaning grace or prosperity. The name originated independently in Ireland and Scotland. "Maqi rati" is engraved on an ancient ogham stone at Keenrath, Co. Cork, Ireland and one Macraith de (of) Ospital, witnessed the gift of a church to the canons of Holyrood, Scotland, in the reign of Malcolm 1V (1154-1165).
In the modern idiom the surname has many variant spellings including McGrath McCrae, McCray, McCrea, McGra, Magraw, etc.. On April 17th 1786, Margaret Jane McGraw married James Brown, at St. Lukes, Chelsea. The marriage of Peter McGraw and Esther McDonald took place on July 7th 1821, at Gorbals, Lanarkshire. The family coat of arms is a shield divided quarterly, on the first there are three red lions passant on a silver background on the second is a right hand holding a blue cross on a gold field, the third depicts a right hand holding a battle-axe on a red background and on the fourth is a black antelope trippant with gold horns on a silver field. The first recorded spelling of the family name is shown to be that of John McCraith, Co. Clare, which was dated 1369, Author of "The Wars of Turlough", during the reign of King Edward 111, "The Father of the Navy", 1327 - 1377. 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.
Notable among the family name at this time was Miler MacGrath (1523-1622), Archbishop of Cashel. Seán mac Ruaidhri Mac Craith ( fl. 14th-century), later known as John Macrory Magrath, was an Irish historian known as the author of Caithréim Thoirdhealbhaigh. Mathghamhain Mág Raith, was Bishop of Killaloe, (1389-1400) and Donatus Mág Raith, O.S.A., was Bishop of Killaloe (1400-1421.) Continuing this line was Thaddaeus Mág Raith I, Bishop of Killaloe (1423-1433) and Thaddaeus Mág Raith II, Bishop of Killaloe, (1460-1463.) Miler Magrath (1523?-1622)
In 1317 a famous battle between two factions of the O’Brien family took place at Corcomroe Abbey located a few miles west of Kinvarra, Co. Galway. century. Members of the Macraith family fought on the side of the descendants of Turlough O’Brien. After the battle the dead were buried on the grounds of the abbey. A detailed account of the battle is contained in “The Battles of Turlough” (Caithreim Toirdhealbhaigh) written in about 1369 by Sean McCraith, a descendant of participants in the battle.