北極圈的定義有很多種，通常指北極圈（66° 34’N） 以北地區。另外也有人以「北極原住民活動範圍」，或以「八個北極圈國家的北方領土」為定義。北極圈主權並沒有像《南極條約》一樣的明確規範，僅有一套1920 年的《斯瓦巴條約》勉強沾得上邊，但也只是說誰可以在北極圈逗留，並沒有畫分主權歸屬。另外還有一個北極理事會(Arctic Council)，但也僅是維繫北極圈脆弱的生態系統、原住民保障等軟性規範。
There are many definitions of the Arctic Circle, but it generally refers to the area north of the Arctic Circle (above 66° 34’N latitude). There are also people who define this area as “the home range of the Arctic indigenous peoples”, or “the northern territory of the 8 Arctic nations.” Territorial claims to parts of the Arctic are not clearly regulated as by the Antarctic Treaty; only the 1920 Svalbard Treaty even comes close, but even then, it only states who can occupy the Arctic Circle without really outlining specific rights over the various territories. Similarly, the Arctic Council merely maintains soft regulations regarding the fragile ecosystem of the Arctic Circle and protection of indigenous peoples.
The “eight arctic nations” is comprised of Canada, the United States, Denmark, Iceland, Norway, Sweden, and Russia, the nations whose geographical territory actually extends into the Arctic Circle. However, in 2018, China proposed the Polar Silk Road plan to claim a stake in the Arctic Circle. Another active player is Russia. The Arctic is highly prized for its rich and yet untapped fossil fuel and natural gas resources, and for being the shortest route between Eurasia and North America. The warmer the earth is, the more intensified the battle over the Arctic will become.