Geographic centre

In geography, the centroid of the two-dimensional shape of a region of the Earth's surface (projected radially to sea level or onto a geoid surface) is often known as its geographical centre. There has long been debate over the methods of calculation of the geographical centres of various countries and regions, such as whether to include offshore islands, and in that case, if the islands should be moved towards the mainland, making it possible to build a connected 2D model of the country and identify the geographical centre as the centre of gravity (equilibrium point) using a needle. An alternative to defining the geographical centre as the centroid is to define it as the point farthest from the boundary of the country (either the sea, or, in the case of constituent countries, a land border), this is similar to the pole of inaccessibility (place furthest from a coastline). These methods can give quite different results.

...
Wikipedia