On the land of Hyrule, players can reach almost all of Hyrule except for the western and northern edges of the map. This area is 10km by 8km, so technically The Legend of Zelda: The breath of the Wild's map is 10km by 8km.
In addition to the playable map, there is a ring of external terrain around the map. The entire external terrain contains dimensions of 16km by 16km. This is the maximum map size that this terrain system can represent in The breath of the Wild'.
There is a ring of distant mountains outside the external landscape, mainly on the west and north sides of the map, whose farthest point from the map center is more than 20km, and the mountains in the southwest corner are about 43km away from the mountains in the northeast.
The largest object on Hyrule, except the sky box, is the distant sea, which is 55 km in diameter.
