James Clark Ross locates the North Magnetic Pole

Background. The North Magnetic Pole is defined as the point where Earth's magnetic field points vertically downward. Early navigators believed compass needles were attracted to a hypothetical magnetic island or Polaris. James Clark Ross, a British naval officer, served under his uncle John Ross during the second Arctic expedition. The expedition was forced to overwinter on the Boothia Peninsula starting in 1829, setting the stage for the 1831 discovery.

Expedition Context. John Ross's second Arctic voyage began in 1829. Ice forced the expedition to stop for four years at the easternmost point of the Boothia Peninsula. James Clark Ross participated in this voyage from 1829 to 1833. The expedition's presence on the peninsula provided the logistical base for the overland journey to locate the magnetic pole, which was situated on the western side of the peninsula at that time.

Discovery. On 1 June 1831, a small party led by James Clark Ross located the position of the North Magnetic Pole. The party included Thomas Abernethy. Ross personally planted the British flag at the pole. This was the first time the pole was physically reached and defined as the point where the magnetic field points vertically downwards, distinct from the geographic north pole.