The South Pole

The South Pole is the southern limit point of the geographic coordinate system. Latitude reaches its minimum value of −90° there; longitude is undefined; every meridian converges. The /learn/the-north-pole support covers the northern counterpart, and the structure of this article parallels it. What sets the South Pole apart is the physical setting: where the North Pole drifts on sea ice over 4 km of water, the South Pole sits on a continent under 2.7 km of ice. The article covers the geometric definition, the four distinct south poles, the physical environment of the polar plateau and the Amundsen-Scott Station, the history of human attainment (uncontested in its key dates, unlike the disputed North Pole record), and the climate that makes the South Pole one of the coldest inhabited places on Earth.

Definition and geometry

The geographic South Pole is the point on Earth's surface where the rotation axis emerges in the Southern Hemisphere. Per the IERS Conventions, the rotation axis is defined by the IERS Reference Pole; the instantaneous pole differs by the polar-motion vector covered in the North Pole article. The instantaneous south pole tracks the instantaneous north pole — they are antipodes by definition.

At the geographic South Pole:

• Latitude is exactly −90°
• Longitude is undefined — every meridian passes through the pole
• Every direction from the pole points north
• Day length is determined entirely by solar declination — six months of daylight (around 22 September to 22 March), six months of polar night (around 22 March to 22 September), with refraction-extended transition periods

The undefined-longitude singularity is the same problem at the South Pole as at the North Pole: coordinate-system code that treats latitude/longitude as a regular grid runs into degeneracies at φ = ±90°. ECEF and unit-sphere representations avoid the issue; specific projections (polar stereographic projections from the South Pole are the standard for high-latitude Southern Hemisphere mapping) place the pole at the centre and are well-defined there.

The four south poles

Four distinct points carry the name “south pole”, mirroring the four north poles:

Geographic South Pole — the rotation-axis intersection at latitude −90°, the focus of this article.

Magnetic South Pole — the point on Earth's surface where the geomagnetic field is vertical, pointing up (out of the Earth) rather than down. Per the NOAA NCEI World Magnetic Model 2025, the Magnetic South Pole is currently at about 64.07°S, 135.88°E — in the Southern Ocean off Adélie Land, more than 2,800 km from the geographic pole. The Magnetic South Pole is dramatically further from its geographic counterpart than the Magnetic North Pole is from its — a consequence of the geomagnetic field's asymmetry. The /learn/the-world-magnetic-model support covers the model.

Geomagnetic South Pole — the intersection of the idealised dipole axis with the surface, currently at about 80°S, 107°E in East Antarctica.

Antarctic Pole of Inaccessibility — the point on the Antarctic continent farthest from any coastline, at approximately 82°06′S, 54°58′E. A Soviet expedition reached the point in December 1958 and built a small station there with a bust of Lenin facing Moscow mounted on top. The Lenin bust is still visible above the slowly accumulating snow; the station is otherwise long abandoned.

Physical setting

The geographic South Pole sits on the East Antarctic Ice Sheet. Per the US Antarctic Program station documentation:

• Surface elevation: about 2,835 m above sea level
• Ice thickness at the pole: about 2,700 m
• Bedrock elevation: approximately at sea level (the bedrock has been depressed about 600 m by the weight of the ice; isostatic rebound would lift it substantially if the ice were removed)
• Surface ice movement: about 10 m per year toward the Weddell Sea (the East Antarctic Ice Sheet drains in several directions; the surface at the pole drifts as the ice flows)

Because the ice flows, the pole marker — a small metal stake placed in the snow — is repositioned every year. The new marker is set on 1 January each year at the actual geographic pole; the previous markers remain in place as a row of stakes trailing off to the side, each year about 10 m further from the true pole than the last. The accumulation of past markers makes the South Pole one of the most visible demonstrations of glacial flow.

The pole sits roughly 1,300 km from the nearest coastline (at the Ross Sea), in the interior of an ice sheet that is on average about 2 km thick over an area roughly the size of the contiguous United States. The surrounding terrain is an essentially featureless plateau — “polar desert” in climatological terms, with little snow accumulation and constant katabatic winds blowing outward from the plateau's centre.

The Amundsen-Scott Station

The first permanent occupation of the South Pole began for the International Geophysical Year of 1957–1958. The original Amundsen-Scott Station was built on the surface in 1956–1957; later stations were built either as raised structures or as buried domes that slowly disappeared beneath accumulating snow.

The current Amundsen-Scott South Pole Station is the third generation: a raised structure on adjustable jacks that can be lifted as snow accumulates beneath it. The new station opened in stages between 2003 and 2008. It houses roughly 150 personnel in the summer (December) season and about 45–50 in winter, when no flights can land (the last flight typically departs in mid-February; the next arrives in late October).

The station hosts the IceCube Neutrino Observatory — a cubic-kilometre detector built into the ice beneath the station — the South Pole Telescope (a 10-m millimetre-wave radio telescope), atmospheric monitoring including some of the longest-running CO₂ measurements in the Southern Hemisphere, and seismographic and geomagnetic monitoring contributing to the IERS reference frame and the World Magnetic Model.

History of attainment

Unlike the North Pole, the South Pole record is largely uncontested:

Roald Amundsen — 14 December 1911. Norwegian expedition with four companions (Olav Bjaaland, Helmer Hanssen, Sverre Hassel, Oscar Wisting) using skis and dog sled, departing from the Bay of Whales on the Ross Ice Shelf. The party reached the pole, raised the Norwegian flag, and named the surrounding plateau Polheim. All five returned safely.

Robert Falcon Scott — 17 January 1912. British Terra Nova expedition with four companions (Edward Wilson, Henry “Birdie” Bowers, Lawrence Oates, Edgar Evans) using a combination of ponies, motor sledges, and man-hauling, departing from McMurdo Sound. The party reached the pole approximately 33 days after Amundsen and found his tent. All five died on the return journey, from a combination of malnutrition, scurvy, cold, and fuel-cache failures. Their bodies and records were found by a search party on 12 November 1912.

Richard Byrd — 29 November 1929. First aircraft overflight of the pole, in a Ford Trimotor from Little America base on the Ross Ice Shelf.

Edmund Hillary and the Commonwealth Trans-Antarctic Expedition — 4 January 1958. First overland party to reach the pole since Scott, using modified Ferguson tractors.

International Geophysical Year occupation — November 1956 onwards. The original Amundsen-Scott Station was constructed and continuously occupied from 1957.

Subsequent firsts have included the first woman at the pole (1969, Pam Young), the first solo unsupported trek (Erling Kagge, 1993), and the first wheeled vehicle (a modified Toyota Hilux in 2007).

The geographic and ceremonial poles

The Amundsen-Scott Station marks two distinct poles a short distance apart:

• The geographic South Pole is the actual latitude −90° point, marked by a small metal stake reset annually as the ice flows. Behind it, a trail of previous-year stakes runs roughly north (every direction from the pole is north, but the ice flow gives them a coherent line). The current stake bears a quotation chosen by the previous summer's crew engraved on a brass plaque.
• The Ceremonial South Pole is a few metres from the geographic pole, with a mirrored steel globe atop a red-and-white-striped pole and a semicircle of flagpoles representing the 12 original signatory nations of the Antarctic Treaty (Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, the Soviet Union/Russia, the United Kingdom, and the United States). The Ceremonial Pole is the place where tourist photographs are taken; it is fixed in place relative to the station and does not move with the ice flow.

Because the ice moves about 10 m per year and the Ceremonial Pole does not, the Ceremonial Pole drifts slowly away from the geographic pole; periodic small adjustments keep the two within a few metres of each other.

Coordinates near the pole

Latitude near the South Pole behaves intuitively — moving north increases latitude from −90° toward the Antarctic Circle at −66.5634°, covered in the /learn/the-antarctic-circle support. Longitude behaves less intuitively because every value is valid within a few metres of the pole.

A useful rule of thumb: at 1 km from the pole, one degree of longitude spans about 17.5 metres of arc; at 100 m from the pole, one degree spans 1.75 m; at 1 m from the pole, one degree spans 1.75 cm. Standing on the pole, you can step around the marker and visit every longitude in a single short circle, crossing every time zone meridian in the process. The Amundsen-Scott Station tradition of “running around the world” at the pole — completing a lap of the marker — is exactly this circular trip across all 360° of longitude.

Polaris and the Southern Cross

The South has no Polaris. The current celestial south pole is in the constellation Octans, an undistinguished area of the southern sky with no bright star nearby; the nearest bright candidate, σ Octantis, is at declination −88°56′57″ — about 1°03′ from the celestial pole — but is only fifth-magnitude, near the limit of naked-eye visibility.

Southern Hemisphere navigators have historically used the Southern Cross (Crux) and the Pointers (α and β Centauri) to estimate the celestial south pole's position. The long axis of the cross points approximately to the pole; combining that line with a perpendicular bisector from the Pointers narrows the location. The technique is less precise than aligning on Polaris but workable; the /learn/celestial-navigation support covers it in more depth.

Earth's axial precession will eventually move the celestial south pole through Carina, then Vela, with several brighter stars passing near the pole over the next several millennia. The nearest moderately bright pole star will be γ Chamaeleontis around AD 4200.

Sources

• US Antarctic Program, Amundsen-Scott South Pole Station — station and geographic details.
• British Antarctic Survey — Antarctic geography and climate.
• NOAA NCEI, World Magnetic Model — Magnetic South Pole position.
• IERS Conventions (TN 36) — IERS Reference Pole.
• Antarctic Treaty Secretariat — treaty framework.
• USGS GNIS — geographic-name authority.

For the northern analogue, see /learn/the-north-pole; for the polar circle that bounds 24-hour day/night phenomena, see /learn/the-antarctic-circle.