The Greatrun River is an unmarked location in Horizon Zero Dawn. It is a river running through the center of the Sundom, in the Greatrun River Canyon, primarily within the Gatelands region. The Carja settlement of Lone Light rests on a cliff overlooking the river, near a bridge along the Way of Broken Stones. It forms the border between the Gatelands and The Jewel.
- Greatrun River Canyon is based on the Colorado River in Utah. It is visually similar to the bend at Dead Horse Point, specifically. 
- Horizon Zero Dawn Strategy Guide (Collector's Ed.), p.527. Future Press, 2017.
- Per Lucas Bolt's Horizon Zero Dawn - Desert Landscapes post.