Landlocked
A landlocked country is one that has no coastline.Historically been regarded as a disadvantageous position. It cuts the country off from makes sea resources such as fishing, but more importantly cuts off access to seaborne trade which even today makes up a large percentage of international trade. Around the world coastal regions tend to wealthier and more heavily populated than inland ones.
Countries thus have made particular effort to avoid being landlocked. For instance when the Democratic Republic of the Congo was created it was given a thin piece of land bisecting Angola to connect it the sea. After WWI Poland was given the Danzig Corridor to give it an outlet on the sea. The successful separatist movement in Eritrea and the current one in Montenegro are of greater concern to their host countries than they would otherwise be as they control the nations' only coastline. The Dubrovnik Republic had once sold the town of Neum to the Ottoman Empire; this small municipality was inherited by Bosnia and Herzegovina and it now provides it with limited sea access, splitting the Croatian part of the Adriatic coast in two.
Some countries may have a large coastline, but no readily useable one. For instance Russia in the sixteenth century can be said to be landlocked as their only ports were on the Arctic Ocean and frozen shut much of the year. Gaining control of a warm water port was a major motivator of Russian expansion towards the Baltic, Black Sea and Pacific Ocean.
An island nation, a country completely surrounded by water is the opposite of a landlocked one.
Landlocked countries
Double landlocked countries (surrounded only by landlocked countries)
See also: List of landlocked subnational entities