Characters named Macha are in some of the most inconcequential and influential of Irish mythology. In the myth The Book of Invasions women named Macha appear 3 times. Twice as humans of absolutely no importance and then as a Goddess of the Tuatha de Danann who gets killed by the cyclopean Balor.
Her most important role is interestingly in a story she doesnt even appear in. In a prequel to Irelands National Epic the Tain/the Cattle Raid of Cooley Macha is a pregnant fairy woman who curses the men of ulster for not treating her with respect. They suffer a pennance of the pain of childbirth during raiding season so they arent able to help the hero of the Tain Cu Chulainn to defend Ulster. It sets the scene for the whole story.
A nice coincidence between myth and archaeology is in the place name stories explaining the name Emain Macha Queen Macha draws the outline of the fort and the hospital with her Brooch and Emain Macha is were a type of penanular brooch was found thats specific to Ulster.