Geographers refer to 'Poles of Inaccessibility' to define locations that are most challenging to reach due to remoteness. It is no surprise therefore that the northern and southern poles of inaccessibility are located in the Arctic and Antarctic respectively. Continental poles of inaccessibility are often hundreds (or thousands) of miles from the nearest coastline, but may not be as remote from population centres.
Antarctica is a large, inhospitable continent that does indeed rank as one of the most extreme and inaccessible places on Earth, but there is a permanently staffed research station there now – so whilst extremely remote, there are people there.
"So, we need an uninhabited island, a long way from civilisation by sea, to get as far away from anyone else as possible."
There are some extremely remote Pacific Islands, but many are populated – so whilst miles away from anywhere else, there is still a small population which counts them out. Russia/Siberia is vast, but small indigenous populations are widespread – and some are seasonally nomadic, which counts that out.
So, we need an uninhabited island, a long way from civilisation by sea, to get as far away from anyone else as possible. The oceanic pole of inaccessibility - Point Nemo; officially the 'middle of nowhere' - is in the centre of the Southern Pacific Ocean, so any land here is likely to be able to boast the furthest place on Earth away from anyone else.
https://www.youtube.com/embed/n4ElF8awm90?wmode=opaque
The most likely candidate is Bouvet Island. This is an uninhabited (Norwegian) island in the Southern Pacific Ocean. The nearest land is an uninhabited part of Antarctica nearly 1,000 miles to the south. The nearest inhabited land is another island – Tristan da Cunha (1,404 miles away) and South Africa (1,603 miles away). You probably don't want to go there on holiday though. The centre of the Bouvet Island is an ice-filled volcanic crater and a glacier covers 93 percent of it. If Bouvet Island gets the prize for the most remote uninhabited place, then Tristan da Cunha wins the most remote inhabited place on earth. Tristan da Cunha (originally discovered by the Portuguese) is another South Pacific island – more precisely, a connected chain of volcanic islands called an archipelago.
"There are some extremely remote Pacific Islands, but many are populated – so whilst miles away from anywhere else, there is still a small population which counts them out."
This group of islands lies 1,200 miles from the nearest inhabited land – another island called Saint Helena, and 1,500 miles from the nearest continent (South Africa). The islands are part of the British Overseas Territory and have a population of around 265 permanent residents (as of 2016). Other notable extreme places include Oymyakon, a remote part of north east Russia which is one of the coldest inhabited locations on earth where the ground is permanently frozen. In 1924, the thermometer dipped to a bone-chilling -71.2 degree Celsius – officially the lowest temperature ever recorded in an inhabited place.