Westeros is long and narrow, bounded by the Sunset Sea to the west and the Narrow Sea to the east. Martin confirmed early on that the continent roughly mirrors South America in vertical length, spanning approximately 3,000 miles from the Wall to the southern coast of Dorne. That distance makes domestic transit a multi-month endeavor for foot soldiers and merchant wagons. The continent divides into distinct ecological zones: subarctic tundra beyond the Wall, dense boreal forests in the North, fertile river valleys in the Riverlands, arid plateaus in the Westerlands, and baking deserts in Dorne.
The North constitutes nearly half the continent's total land area, yet its population density sits far below the central and southern provinces. South of the Neck, a treacherous swamp that forms a natural bottleneck guarded by the ruins of Moat Cailin, the terrain becomes agrarian. The Reach serves as the agricultural core, producing grain and wine along the river Mander.
Because distances are so immense, mobilization takes months. An army marching south from Winterfell to King's Landing along the Kingsroad covers roughly 1,500 miles. Moving 20,000 men at an average pace of 12 to 15 miles per day requires more than three months of continuous travel, exposing marching columns to attrition, disease, and forage depletion. Flight by dragon reduces that timeline to days, explaining why aerial dominance completely rewrites tactical geography throughout regional conflicts.
