Poles of Inaccessibility

A Pole of Inaccessibility is the location in a country which is furthest from the sea. A Pole of Inaccessibility can be defined as being the center point of the largest circle that can be drawn within a country without encountering a coastline. 

You can discover the furthest point from the coastline in every single country on Karim Douïeb's Observable notebook the Pole of Inaccessibility of Every Country. On this interactive map the largest possible circle (without encountering a coastline) has been drawn on every country. The Pole of Inaccessibility for each country is at the exact center of its circle. If you click on country's circle on the map then Google Maps will open showing the actual location of that country's Pole of Inaccessibility. 

Atlas Obscura has also worked out a number of Poles of Inaccessibility. Their collection of points on the Earth which are hard to access include the Arctic Pole of Inaccessibility (the northernmost point that is furthest from land), the Eurasian Point of Inaccessibility (the point on the Eurasian continent that is furthest from the ocean) and the North American Pole of Inaccessibility (the spot in North America furthest from the coast).

A Pole of Inaccessibility doesn't actually have to be the furthest point from the sea. You can use other entities from which to measure the furthest distance from. For example seas & oceans can have Poles of Inaccessibility which are calculated as being the furthest points from land.Another way to work out Poles of Inaccessibility might be to find the locations furthest away from a road.

Places of Inaccessibility is an interactive map which shows Germany's most inaccessible locations for car drivers. The map visualizes the points in Germany which are the furthest away from a road. Großer Knechtsand is Germany's Pole of Inaccessibility being 13.59 km from the nearest road. Part of the reason it is so far from a road is because it is on a road free island. A point in a military training area in Bergen is the most inaccessible place that is neither in the water, on an island or in the mountains.