The Sea East is one of the principal bodies of water mentioned in the Book of Mormon, located to the east of Nephite and Lamanite lands. It served as a significant geographical landmark in the mapping and division of territories between these two civilizations. The narrow strip of wilderness, an important feature in the demarcation of Nephite and Lamanite lands, ran from the Sea East to the Sea West, effectively separating the Land of Zarahemla from the land occupied by the Lamanites (Alma 22:27). This narrow strip of wilderness extended from the sea on the east to the sea on the west, encapsulating the borders of the seashore and adjoining the wilderness at the northern territories by the land of Zarahemla.
As the Nephite population began to prosper and rebuild their society after periods of conflict and natural disaster, they expanded their territory until they covered the whole face of the land from the Sea West to the Sea East, indicating a substantial geographical spread of Nephite settlements (Helaman 11:20). This eastward expansion reflected the growth and diffusion of Nephite civilization across the promised land. Helaman 3:8 further attests to the Nephites’ spread from the land south to the land north, and from west to east, indicating that their domain eventually reached the Sea East. This expansion underscores the significance of the Sea East as a geographical boundary of their lands and a marker of Nephite growth and influence.