Antarctic Circle

The sun on the Antarctic Circle

How to use it

1. The line is drawn in orange across the whole map as soon as the page opens.
2. Pan and zoom to follow it. On the web map's Mercator projection, parallels are straight horizontal lines and meridians straight vertical ones.
3. Under the map, read the list of countries whose land the line crosses and the notes about the line.
4. Use the other line pages linked below to compare positions, or the miles per degree calculator for the length of a degree at this latitude.

Why the Antarctic Circle is where it is

The Antarctic Circle is the southern polar circle, at 66.5606° S. South of it the sun stays up all day around the December solstice and stays down all day around the June solstice. Almost all of the land it encloses is the Antarctic continent.

No country is crossed in the usual sense. Natural Earth maps the whole continent as one unit, Antarctica, and territorial claims there are held in abeyance under the Antarctic Treaty.

How long the line is

A parallel is a circle whose radius is the distance from the Earth's axis. On the WGS84 ellipsoid that radius is N · cos φ, where N is the prime vertical radius of curvature, which at 66.5606° S is 6,396,184 m. The circumference 2π · N · cos φ comes to 15,986.1 km.

One degree of longitude along it is 44.41 km, or 27.59 miles. The miles per degree calculator gives the same figure for any latitude.

Countries on the line

The map draws the line itself. No country list is given here, because the line's position follows national choices rather than a single parallel or meridian.

• The circle encloses most of Antarctica.
• National claims are governed by the Antarctic Treaty System.

The United States and this line

The United States has no territory near the Antarctic Circle. Its research stations operate under the Antarctic Treaty system. From Denver's capitol to the circle along a meridian is 7,323 miles.