The King’s River flows through the city, spilling into an eroded chasm in the northwest corner and flowing down to the Bay of Ptolus near the Docks. The bottom of the chasm, called the King’s River Gorge, is eighty feet below the level of the ground on its north side, but more than two hundred feet below on its south side.

The south side still holds the old city walls and fortifications. A bridge built upon two massive pillars, themselves erected atop natural rock columns, stretches across the King’s River Gorge at a steep angle, leading into the area of the city known as Oldtown. Another bridge stretches across the chasm to join Oldtown with the Rivergate District. Although Oldtown is higher, the difference in elevation between these two districts is not steep, so the slope of this bridge seems far less noticeable than that of the other.

The King’s River cuts through the center of town, flowing east to empty into the Bay of Ptolus. The river comes into town from the north and west, cutting a wide swath north of Oldtown called the King’s River Gorge. The gorge separates Oldtown from a small residential district to the northeast called Rivergate. At the end of the gorge, the river plummets down two hundred feet in a tall waterfall, to flow more gently and toward the bay within narrower and more modest banks. The King’s River, which effectively cuts the city in half, is spanned by no fewer than twelve bridges.

The King’s River runs through Palastan, a fairly slow and inconsequential waterway throughout most of its course. When it nears Ptolus, however, runoff from the Spire and the area’s frequent rains feeds into the river, making it much faster and more substantial. The river skirts the northern edge of the Spire to pour into the King’s River Gorge in a two-hundred-foot plunge. The waterfall here is called the King’s Falls. When it leaves the gorge, it runs into a narrow channel between Rivergate and Oldtown and down Wings Falls. The channel the King’s River cuts through the rest of the city usually is no more than sixty or seventy feet across, but it measures up to one hundred feet deep as the land slowly slopes toward the shoreline. When the river reaches the Bay of Ptolus, it spews forth from the Cliffs of Lost Wishes in a grand, four-hundred-foot waterfall called Gasping Falls.

In the city the river is entirely unnavigable, being far too rapid and with too many waterfalls as it courses to its final drop into the sea. Since the river is not used as a source of water for the city (it gets its water from much cleaner underground wells), the sewers pour into it from both sides of its narrow channel. Likewise, residents dump trash and refuse of all kinds into the river as it roars through its ravine. This is one of Ptolus’ main sources of refuse disposal, which speaks to the degree of contamination in the river.