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The longest border between any two countries in the world is between :
Explanation
The longest international land border in the world is between Canada and the United States, measuring 8,893 km in total length[2]. This makes option A the correct answer.
The second longest land border is between Kazakhstan and Russia at 7,644 km[3], making option D incorrect. The third longest border is between Chile and Argentina at 6,691 km[4], which eliminates option B. Option C (China and India) is also incorrect as the China-Russia border is 4,133 km and the Bangladesh-India border[5] is 4,142 km, indicating that the China-India border would be even shorter and not among the world's longest borders. The Canada-US border's exceptional length is due to the vast geographical extent of both countries across the North American continent.
SourcesPROVENANCE & STUDY PATTERN
Guest previewThis is a classic 'Atlas Superlative' question. While standard textbooks (NCERT/Majid Husain) focus heavily on India's borders (India-Bangladesh being #1 for India), they rarely explicitly list the global ranking. This question rewards the 'curious mapper' who checks the 'World Statistics' appendix in their Oxford/Blackswan Atlas rather than just reading text.
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
Web source
Presence: 5/5
"## 1. Canada–United States - 8,893 km [Canada], the world’s second largest country, shares the longest international land border with the United States."
Why this source?
- Explicitly labels Canada–United States as #1 on a ranked list of longest land borders.
- Gives a specific length (8,893 km) and states it is the longest international land border.
Web source
Presence: 5/5
"Canada and the U.S. share the longest international land border in the world — 5,525 Miles in total."
Why this source?
- Directly states Canada and the U.S. share the longest international land border in the world.
- Provides the total length in miles (5,525) and explains the border is in two sections (Alaska/continental).
Web source
Presence: 4/5
"The longest land border in the world is between Canada and the United States (US). The total length of the border between the US and Canada is 8,893 km."
Why this source?
- States the longest land border in the world is between Canada and the United States.
- Provides a numeric length (8,893 km) for the Canada–US border.
- Explicitly labels Canada–United States as #1 on a ranked list of longest land borders.
- Gives a specific length (8,893 km) and states it is the longest international land border.
- Directly states Canada and the U.S. share the longest international land border in the world.
- Provides the total length in miles (5,525) and explains the border is in two sections (Alaska/continental).
- States the longest land border in the world is between Canada and the United States.
- Provides a numeric length (8,893 km) for the Canada–US border.
Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 16: India–Political Aspects > INTERNATIONAL BOUNDARIES OF INDIA > p. 28
Strength: 5/5
“Sri Lanka is separated from India by a narrow channel of sea formed by the Palk Strait and the Gulf of Mannar. The longest border of India is with Bangladesh (4096 km), followed by China, Pakistan, Nepal, Myanmar, Bhutan, and Afghanistan. The shortest border of India is with Afghanistan being only 80 km (Table 16.2).”
Why relevant
Gives a concrete example of a very long international land border (India–Bangladesh = 4096 km), establishing a benchmark for 'very long' bilateral land borders.
How to extend
A student could compare known lengths of other long borders (e.g., Canada–USA) against this 4096 km benchmark using a world map or reference to judge which is longer.
Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 16: India–Political Aspects > The Sino-Indian Border Dispute > p. 29
Strength: 5/5
“India's border with China is 3917 km. which is about 26% of the total land border of the country. Five Indian states, namely, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim and Arunachal Pradesh share the border with China (Fig. 16.2). This boundary is the product of Manchu policy, Chinese Republican policy, and the British policy. Since the topographical features are rugged folded mountains, and the climate harsh, it was not possible to demarcate the boundary on the ground. The boundary was, however, demarcated on the maps. The boundary remained peaceful till India achieved Independence in 1947, and the Communist takeover of China on October 1, 1949.”
Why relevant
Provides another large border length (India–China = 3917 km) and frames border length as a measurable attribute of countries.
How to extend
Use this numeric example as a second comparison point when assessing whether any other bilateral border (such as Canada–USA) exceeds these lengths.
Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 16: India–Political Aspects > India-Nepal Boundary > p. 46
Strength: 3/5
“India's border with Nepal is 1752 km. Five states of India, namely, Uttarakhand, Uttar Pradesh, Bihar, West Bengal and Sikkim touch the border of Nepal (Fig. 16.7). India-Nepal border, mainly runs in a westeast direction almost along the foothills of the Siwalik Range. A treaty between British and Nepal government was signed in 1814–15. This treaty was ratified in March 1916. Under the terms of the Treaty, the Himalayan districts of Nainital, Almora, Garhwal, Dehra Dun, and Shimla were annexed by the British. (Karan, et.al. 1963). The eastern tracts were given to Sikkim. The present boundary between India and Nepal is the boundary demarcated in 1858.”
Why relevant
Supplies a mid-range border length (India–Nepal = 1752 km), demonstrating variation in border lengths and helping to contextualize what 'long' means.
How to extend
A student can place this value among other known border lengths to form a ranked sense of border magnitudes before checking the Canada–USA figure externally.
Themes in world history, History Class XI (NCERT 2025 ed.) > Chapter 6: Displacing Indigenous Peoples > ACTIVITY 1 > p. 142
Strength: 3/5
“The countries that are known as Canada and the United States of America came into existence at the end of the eighteenth century. At that time they occupied only a fraction of the land they now cover. Over the next hundred years they extended their control over more territory, to reach their present size. Large areas were acquired by the USA by purchase – they bought land in the south from France (the 'Louisiana Purchase') and from Russia (Alaska), and by war – much of southern USA was won from Mexico. It did not occur to anyone that the consent of natives living in these areas should have been asked.”
Why relevant
Notes the large territorial expansions of Canada and the USA over the 18th–19th centuries, implying they are geographically large contiguous states likely to share an extensive boundary.
How to extend
Combine this historical-geographic hint with a world map to infer that a long shared frontier is plausible and should be checked against numeric border-length data.
Gives a concrete example of a very long international land border (India–Bangladesh = 4096 km), establishing a benchmark for 'very long' bilateral land borders.
A student could compare known lengths of other long borders (e.g., Canada–USA) against this 4096 km benchmark using a world map or reference to judge which is longer.
Provides another large border length (India–China = 3917 km) and frames border length as a measurable attribute of countries.
Use this numeric example as a second comparison point when assessing whether any other bilateral border (such as Canada–USA) exceeds these lengths.
Supplies a mid-range border length (India–Nepal = 1752 km), demonstrating variation in border lengths and helping to contextualize what 'long' means.
A student can place this value among other known border lengths to form a ranked sense of border magnitudes before checking the Canada–USA figure externally.
Notes the large territorial expansions of Canada and the USA over the 18th–19th centuries, implying they are geographically large contiguous states likely to share an extensive boundary.
Combine this historical-geographic hint with a world map to infer that a long shared frontier is plausible and should be checked against numeric border-length data.
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