Katun Nature Reserve (Russian: Катунский заповедник) (also Katunsky) is a Russian zapovednik (strict nature reserve) located in the highlands of the central Altai Mountains of south Siberia. The Katun River runs down through a valley in the reserve, serving as the primary source of the Ob River. The headwaters of the Katun River originate on Mount Belukha, the highest mountain in Siberia at 4,506 metres (14,783 ft), which is located on the far eastern edge of the preserve. Katun is an internationally important center of biodiversity, forming part of the "Golden Mountains of Altai" UNESCO World Heritage Site. Katun Nature Reserve is situated in the Ust-Koksinsky District of Altai Republic.