Utter East

The Utter East is the eastern-most edge of the world of Narnia. It is a notable section of the End of the World, since it is from here that the sun rises.

Appearance
The water of the Great Eastern Ocean is held back by a great standing wave, over twenty feet high, that sits at the edge of the world. The sun rises from behind this standing wave, which is why it appears so close the further east one is.

Beyond
Beyond the Utter East lies Aslan's Country atop a high mountain.

The Voyage of the Dawn Treader
King Caspian X and the crew of the Dawn Treader sailed from Narnia ostensibly to find the Seven Lost Lords that his uncle, Miraz, sent away as they would not be loyal to him. However, the larger reason was to explore the great unknown expanse of the Eastern Ocean. Reepicheep, the mouse, hoped that they would arrive at the Utter East, where he would leave the world altogether and come into Aslan's country.

Along the way, they were met by Lucy, Edmund, and Eustace, who joined them on their quest.

At the Utter East, the three children and Sir Reepicheep left via the boat and paddled to the edge. Reepicheep then took his coracle and paddled over the great standing wave and entered Aslan's country. The children found a small strip of land that was the End of the World and followed it until they met Aslan himself, who returned them to England.

The Silver Chair
Eustace and Jill Pole returned to Aslan's country beyond the Utter East from Experiment House. When Eustace accidentally falls off the mountain, Aslan blows him on his breath to Narnia. Both children sail over the Utter East and the seas around it while so far above it that the clouds look like the ground.