Its border with Zambia to the north near Kazungula is poorly defined but is, at most, a few hundred metres long.
A mid-sized country of just over 2 million people, Botswana is one of the most sparsely populated countries in the world.
The arrival of the ancestors of the Tswana-speakers who came to control the region has yet to be dated precisely.
Stone tools and fauna remains have shown that all areas of the country were inhabited at least 400,000 years ago.
The original inhabitants of southern Africa were the Bushmen (San) and Khoi peoples.
It is unclear when Bantu-speaking peoples first moved into the country from the north, although AD 600 seems to be a consensus estimate.
In that era, the ancestors of the modern-day Kalanga moved into what is now the north-eastern areas of the country.