The 73rd parallel north is a circle of latitude that is 73 degrees north of the Earth's equatorial plane, in the Arctic. It crosses the Atlantic Ocean, Europe, Asia, the Arctic Ocean and North America.
At this latitude midnight sun lasts from about May 4th to August 7th, and polar night from about November 12th to January 29th, with nautical polar twilight lasting from about December 11th to January 1st. At noon on the summer and winter solstices, the altitude of the sun is 40.45° and -6.44° respectively. At midnight on the summer solstice, the altitude of the sun is 6.57°.
Starting at the Prime Meridian and heading eastwards, the parallel 73° north passes through:
Between 1776 and 1950, the 73rd parallel formed the northern limit of the Royal Greenland Trade Department's exclusive monopoly on trade near the Dano-Norwegian and later Danish colonies of Greenland (1776 - 1782) and North Greenland (1782 - 1950).[1]