I have often heard the border between the United States and Canada is the world's "longest undefended border", although the presence of the heavily equipped US Border Patrol might contradict that assertion. But there is another rather obvious fact about the United States/Canadian border, or at least a large section of it, that might escape those of us living in the United States, is that it is perfectly straight, built along geographic lines. The largest of these are the 49th parallel, in the contiguous states, and the 141st meridian, between Alaska and the Yukon Territory.
Living in the United States, straight borders might not seem too odd, because many of our smaller units of government, such as states and counties, have straight line boundaries. But such perfectly geometrical states such as Colorado and Wyoming are a rarity in the world. Most of the world's borders follow geological, not geometrical patterns, twisting and turning as rivers and mountains demand. The areas with straight borders are mostly colonial areas that were divided up, haphazardly.
Straight borders of the world include:
The Americas
Africa
- A series of borders between Morocco, Mali, Mauritania, Algeria, Libya, Chad and the Sudan. Most of these borders run through areas of the Sahara Desert that are essentially unpopulated, and therefore don't divide populations.
- The borders between Kenya, Uganda and Tanzania around the area of Lake Victoria are straight.
- As are some of the borders between Angola, The Democratic Republic of the Congo, Namibia, Zambia, Botswana and South Africa.
Asia
- Many of the borders in the Arabian peninsula, as well as parts of the border between Iraq, Syria and Jordan
- Parts of the borders in Central Asia, between Turkmenistan, Uzbekistan and Kazakhstan are straight. At the time these borders were established, these countries were sub-national units, and the borders were administrative, but they have followed them into nationhood.
- Two of histories great failed straight borders, between North and South Vietnam, and between North and South Korea, were in Asia.
Australia
- The border between the Indonesian and Papuan parts of New Guinea is straight, and is one of the world's least accessible borders.
Europe
- Two somewhat trivial examples: Vatican City and Monaco both have straight borders.
In general, straight borders tend to fit into three categories: the
sui generis example of the United States and Canadian border, where the friendly relations and shared culture make the geographical border a non-impediment to life (no one has been "cut off" from their community due to the border), areas where the border doesn't effect people because it goes through uninhabited areas, such as in the deserts of Africa and Southwest Asia (up until an oil field is found between them), and the unfortunate places where a colonially dictated border divides up natural communities.