The 10 km long and 52 metres deep Rõuge primeval valley includes seven lakes: Kahrila Lake, Tõugjärv, Ratasjärv, Kaussjärv, Rõuge Suurjärv, Liinjärv, Valgjärv. The lakes are connected by the Rõuge or Ajo River, which begins in Tindiorg Valley. Rõuge primeval valley has a number of side valleys: Tindiorg, Külmorg, Mõhkorg, Ööbikuorg, Tinopeetri, Hinni, Sikasoo, and Järveotsa. The most famous of those is the 300 m long and 12-15 m deep Ööbikuorg by the northern border of the ancient castle hill. In spring, when the bird-cherry is blooming, the valley is full of the sound of singing nightingales, which is where its name comes from – Ööbikuorg is Estonian for Nightingale Valley. On the edge of Ööbikuorg, there is the Ööbikuorg visitor centre, where visitors can learn about the nature, history, and climate change.