Edge Quote 2

Then Gangleri replied: ‘What did Bor’s sons do then, if you
believe that they are gods?’

High said: ‘There is not just a little to be told about that. They
took Ymir and transported him to the middle of Ginnungagap,
and out of him made the earth, out of his blood the sea and the
lakes. The earth was made of the flesh and the rocks of the bones,
stone and scree they made out of the teeth and molars and of the
bones that had been broken.’

Then spoke Just-as-high: ‘Out of the blood that came from his
wounds and was flowing unconfined, out of this they made the
sea with which they encompassed and contained the earth, and
they placed this sea in a circle round the outside of it, and it will
seem an impossibility to most to get across it.’

Then spoke Third: ‘They also took his skull and made out of it
the sky and set it up over the earth with four points, and under
each corner they set a dwarf.

- Prose Edda, Gylfaginning


(Note: Some may argue with me here over using this excerpt to say that the sea has an edge. I believe that the line "it will seem an impossibility to most to get across it" does indeed imply that the sea has an edge. It only says that it "seems" like it's impossible to get across "to most," which implies that it only appears impassable, and that some could cross it. Similar "seems to most" language to this is used in every translation I've read. Remember that Odin is the one talking here - he shaped the sea with his brothers, so I think he'd know about it. Additionally, this section provides additional support to the concept that the earth has an edge, as the sea is able to "encompass" it.)