The mountain range that separates India and China is the Himalayas. This vast range stretches about 1,500 miles across five countries: India, China, Nepal, Bhutan, and Pakistan

. The Himalayas form a natural barrier between the Tibetan Plateau to the north (China) and the Indian subcontinent to the south (India)

. Additionally, in the western part of the border region, the Karakoram Range also plays a role in separating parts of India and China, especially in the Ladakh area where the Karakoram extends into disputed territories controlled by India, China, and Pakistan

. In summary:

• The primary mountain range separating India and China is the Himalayas.
• The Karakoram Range also forms part of the boundary in the northwest, particularly around Ladakh

Both ranges are part of the complex mountainous terrain that defines the India-China border region.