The name of Grimes or Grymes is believed to be of Scandinavian origin and to have been derived from the ancient Anglo-Saxon baptismal name of Grim, being adopted as a surname by the sons of one so called. It is found in Ancient British and early American records in the various spellings of Grim, Grims, Gryms, Gryme, Grime, Grymes, Grimes and others, of which the form last mentioned is most generally used in America today.
Families of this name were to be found at early dates in the English counties of Cambridge, Norfolk, Surrey, York, Warwick, Chester, and London. Records indicate that they were, for the most part, of the landed gentry of Great Britain.
old scandinavian(viking) personal name GRIMR (websters)
meaning :-'Grimr' is another word for Odin (??din) n.the principal god of pagan Scandinavia, associated esp. with warfare and magically acquired knowledge. [< ON athinn; c. OE W?den, OS Woden, OHG Wuotan; cf. WODEN] also conected to grim (grim) adj., grim?mer, grim?mest 1. stern and admitting of no compromise; harsh; unyielding: grim determination. 2. of a sinister or ghastly character: a grim joke. 3. having a harsh, surly, forbidding, or morbid air: a grim countenance. 4. fierce, savage, or cruel: War is a grim business. 5. Informal. unpleasant. [bef. 900; ME, OE; c. OS, OHG grimm, ON grimmr]? grim?ly adv.? grim?ness n. (websters)
see also "The Oxford Dictionary of English Place-Names" by A.D.Mills and it's references on 'Grimsargh','Grimsby','Grimscote','Grimsthorpe' and 'Grimton'.