Paektu Mountain or Baekdu Mountain is an active stratovolcano on the Chinese–North Korean border. In China, it is known as Changbai Mountain. At 2,744 m (9,003 ft), it is the tallest mountain in North Korea and Northeast China and the tallest mountain of the Baekdu-daegan and Changbai mountain ranges. The highest peak, called Janggun Peak, belongs to North Korea. The mountain notably has a caldera that contains a large crater lake called Heaven Lake, and is also the source of the Songhua, Tumen, and Yalu rivers. Korean and Manchu people assign a mythical quality to the mountain and its lake, and consider the mountain to be their ancestral homeland.

The China–North Korea border is an international border separating China and North Korea, extending from Korea Bay in the west to a tripoint with Russia in the east. The total length of the border is 1,352 kilometers (840 mi). The current border was created by two secret treaties signed between China and North Korea in 1962 and 1964.