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World’s Longest International Borders, at a glance
Two different measures crown two different winners
8,891 km
Canada-US border, longest by total length.
7,644 km
Kazakhstan-Russia border, longest continuous stretch.
5,308 km
Chile-Argentina border, along the Andes.
3,488 km
India-China border, as per India, including Aksai Chin.
Which Border Is Actually the Longest?
Why do two different countries both claim “the longest border”?
- The Canada-United States border is the longest international border in the world by total length, at 8,891 km. That combines 6,416 km with the contiguous US and 2,475 km with Alaska.
- The Kazakhstan-Russia border runs 7,644 km. It is the longest continuous, unbroken international border in the world, second only to Canada-USA’s total.
- Canada-US wins on combined total length, across two separate border segments. Kazakhstan-Russia wins instead as one single, unbroken line.
- India puts its border with China at about 3,488 km, including Aksai Chin. That is far shorter than either of the above. China contests this border in several sectors, the kind of boundary dispute covered in major international boundary lines.
Q1. True or False: The Canada-United States border is the longest international border in the world by total length.
Q2. True or False: The Kazakhstan-Russia border is longer than the Canada-US border in total length.
What Other Long Borders Are Worth Knowing?
Which other borders show up often in exam questions?
- At roughly 5,308 km, the Chile-Argentina border is one of the world’s longest too, running largely along the Andes mountain range.
- The Canada-US border is famously called the world’s longest “undefended” international border, without permanent military presence along most of it.
- The Peace Arch, straddling this border in British Columbia/Washington state, was built in 1921 to commemorate a century of peace between the two nations.
- Border length measures land boundary only, distinct from a country’s total coastline length, a common source of confusion in geography questions, much like mixing up which countries actually border the North Sea.
Q3. True or False: The Canada-US border is often called the world’s longest “undefended” international border.
Q4. True or False: The Chile-Argentina border runs largely along the Amazon River basin.
Think it through, before reading on. Both Canada-US and Kazakhstan-Russia get called “the world’s longest border” in different sources. How can both statements be true at once?
Show the explanation
They are each the longest by a different measure. Canada-US’s 8,891 km is a total across two separate segments: a long stretch with the contiguous US, plus a second, disconnected stretch with Alaska. Kazakhstan-Russia’s 7,644 km is one single, unbroken line, with no gap, making it the longest continuous border rather than the longest in total. An exam question that doesn’t specify “by total length” or “continuous” is testing whether you know this distinction exists at all.
Remember the trap. Canada-US wins on total length (8,891 km, across two segments). Kazakhstan-Russia wins on one continuous stretch (7,644 km). They are not the same claim, and exam options often swap them.
Quick Q&A
What is the world’s longest international border by total length?
Canada-United States, at 8,891 km.
What is the world’s longest continuous, unbroken international border?
Kazakhstan-Russia, at 7,644 km.
How long is the India-China border, as per India?
Around 3,488 km, far shorter than either of the above.
Which long border runs largely along the Andes?
The Chile-Argentina border, at roughly 5,308 km.
- UPSC CSP 2024 — Asked which pair of countries shares the world’s longest international border, among Canada-US, Chile-Argentina, China-India, and Kazakhstan-Russia. The correct answer is Canada-US, by total length. View this paper →
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