Argentina – Chile: 5,300 km (3,293 miles): Argentina is the 8th largest country in the world.
United States – Mexico: 3,141 km (1,951 miles): While the United States shares a land border only with Canada and Mexico.
Russia – Mongolia: 3,543 km (2,201 miles): Amazingly, three of Russia’s 14 land borders are among the world’s 10 longest land borders.
Canada – United States: 8,893 km (5,525 miles): Canada, the world’s second largest countr.
Russia – China: 3,645 km (2,265 miles): Back to China and Russia: Despite the fact that Mongolia and Kazakhstan .
Brazil – Bolivia: 3,400 km (2,112 miles): Back to South America, Brazil is the 5th largest country in the world, and shares a land border with 10 countries.
Russia – Kazakhstan: 6,846 km (4,254 miles): Russia is the largest country in the world.
China – Mongolia: 4,677 km (2,906 miles): China is the third largest country in the world.
India - Bangladesh: 4053 km { 2,518 miles }
China – India 3,380 km (2,100 miles): The China – India border is China’s third longest land border and India’s second longest.