

The north side of the mouth is part of Haafingar, and it is mostly a steep cliff side with very little docking space, with the exception of Solitude. At this point, the river has reached sea level and it is now a long stretch of water to an estuary, the Mouths of the Karth, which the Hjaal River also empties into. The river continues northeast, down rapid streams to calm waters next to Dragon Bridge. At this point, you will find fish that are commonly found in northwest Skyrim, such as the Chillwind Pike, the Morthal Longfin, and the elusive Blue Muskie. The landmark known as Bruca's Leap is found on the north side of the lake, and it is sometimes used as a campsite by the Reachfolk. It empties into a small lake that has another water source coming from the west near Deep Folk Crossing. The river drastically turns northwest right on the Hold's border, and moves across the hinterlands of Karthald and Haafingar. The river diverges to the northeast instead and it streams along until it reaches the edge of the Reach and arrives on the historic territory of Karthald. This water runs down from the Lover Stone to the northwest, Karthmad and Markarth to the west, and Reachwater Rock to the southwest. The other side continues in the same direction, and even has several more water sources intersecting it. One side goes directly north and swerves around the mountain, creating a steep valley and meeting the river back on the northern base. Eventually, the river starts to split at the southern base of Karthspire.

The Karth River moves slightly northwest along the main road, through various waterfalls and around jagged rocks. Throughout the river is a variety of aquatic fauna, mostly the common type like the salmon and river betty, but the Reach in particular contains the valuable Lost Valley Tench and the Nchuand Cavetrout, but also rare fish like the Blackreach Pilgrim and the Fretfish.

From there, the water flows into twin aqueducts which empty into a small lake on the ground level, where the Karth River starts to flow down into the rest of the region. That water comes down from a waterfall and into a man-made pool at Lost Valley Redoubt. The Karth River starts in the alps of the Druadach Mountains, from the mountain called Bard's Leap Summit.
