Located within the central part of the lowlands is the "Central Belt", a rectangle of land roughly 88 kilometres (55 miles) from West to East and 48 kilometres (30 miles) North to South. About half of the population of Scotland lives within these roughly 4,530 square kilometres (or 1,750 square miles), which is a little more than 2% of the total land area of Scotland. This is the area between Scotland’s two largest cities - Glasgow, at the Central Belt’s Western end, and Edinburgh, at the Central Belt’s Eastern end. This area is geographically bound by two bays of water – the Firth of Clyde to the West and the Firth of Forth to the East. It is the most fertile Earth in Scotland, which is why it is so population-dense, compared to the rest of the country.