The Greenblood is the main river of Dorne, from from west to east through the centre of the region. It flows into the Summer Sea just north of Lemonwood. The Greenblood is formed from the confluence of two other rivers, the Scourge and the Vaith, which meet near the castle of Godsgrace.
In the books
In the A Song of Ice and Fire novels, the Greenblood serves as the primary transport and trade artery of eastern Dorne. The country's main port, the Planky Town, is located at the mouth of the river. Due to the desert environment of central and western Dorne, much of the population is concentrated in Dorne's few river valleys such as that of the Greenblood.
It is home to a unique gypsy-like culture known as the "Orphans of the Greenblood", descended from some of the original Rhoynar who chose not to abandon any of their original culture from Essos when they migrated to Dorne. Most of the rest of the Rhoynar did partially assimilate, becoming the present-day Dornishmen. The Orphans of the Greenblood, however, remain a river-based trading society moving up and down the course of the river on boats, and still practicing the original religion of the Rhoynar centered on worshipping river-gods like Mother Rhoyne. In this sense, the Greenblood and its tributaries serve as replacements for the considerably larger Rhoyne and its many branches.