The Sirith is a river in Gondor that rises in the White Mountains in eastern Lebennin, and flows southward. South of the last outliers of the mountains it is joined by a tributary, the River Celos. At the point where it met the Great River Anduin, the port of Pelargir was built.
The Sirith is in the area of Upper Lebennin in the Eastern Gondor region. It flows through the fortified valley of Tumladen before turning west to meet the Celos below the beacon Sirthanc. The town of Erynos is located on the western shore across from where the two rivers meet. South of the juncture, the two joined rivers flow south from the beacon to the Anduin, forming the boundary with Lower Lebennin and the region of Central Gondor. The combined river also bisects the port city of Pelargir where it joins the Anduin. The Sirith is the domain of the honest River-maid Truetongue, one of the Five Sisters, though she and her sisters were widely considered a myth by the time of the War of the Ring.
Like the other Five Sisters, the Serni pours from the White Mountains in a series of waterfalls.
The first stretch of the river is located inside the fortified settlement of Tumladen
As the river gets caught in patches of giant water reeds, the Sirith's river-maid Truetongue watches on.
After the spans of Tumladen, only a single ford crosses the river, leading up to the beacom of Sirthanc.