After the final demarcation carried out in the early 2000s, it measures 4,209.3 kilometres (2,615.5 mi),[3] and is the world's sixth-longest international border.

[5] It starts at the eastern China–Mongolia–Russia tripoint (49°50′42.3″N 116°42′46.8″E / 49.845083°N 116.713000°E / 49.845083; 116.713000), marked by the border monument called Tarbagan-Dakh (Ta'erbagan Dahu, Tarvagan Dakh).

The much shorter (less than 100 kilometres (62 mi)) western border section is between Russia's Altai Republic and China's Xinjiang.

However, just a few months later the USSR was dissolved, and four former Soviet republics — Russia, Kazakhstan, Kyrgyzstan, and Tajikistan — inherited various sections of the former Sino–Soviet border.

The last unresolved territorial issue between the two countries was settled by the 2004 Complementary Agreement between China and Russia on the Eastern Section of the China–Russia Boundary.

The transfer was ratified by both the Chinese National People's Congress and the Russian State Duma in 2005, thus ending the decades-long border dispute.

[19] Detained illegal border crossers are supposed to be normally returned to their country of origin within 7 days from their apprehension (Article 34).

[19] A list of ports-of-entry on the eastern section is provided by China Association of Port-of-entry: connects G1211 (with indirectly G202, G331, G603 and G604), part of AH31 According to Russian topographic maps, the lowest mountain passes on the western section of the border are the Betsu-Kanas Pass (перевал Бетсу-Канас), elevation 2,671.3 metres (8,764 ft)[11][49] and Kanas (перевал Канас), elevation 2,650 metres (8,690 ft).

[49] Proposals exist for the construction of a cross-border highway and the Altai gas pipeline from China to Russia, which would cross the western section of the Sino-Russian border.