Group A runes were most common in Viking Age Denmark
Old Norse Inga (f.)
Inga is very common in Denmark and Sweden (where it appears in a number of runic inscriptions) and probably spread from these two areas into Norway in the thirteenth century. where the name remained popular thereafter; however, it is also possible that Inga developed independently in Norway. In the Danelaw, Inga appears in medieval documents from Lincolnshire as early as c. 1160.
The name is a short form of Old Norse female names in Ing(i)-, which is of doubtful origin but perhaps related to a Greek word meaning ‘lance, staff’.