The Borealis quadrangle is a quadrangle on Mercury surrounding the north pole down to 65° latitude (see also: geography of Mars).
It contains the Goethe Basin, whose diameter of at least 400 km (250 mi) makes it the sixth-largest impact basin observed on Mariner 10 images(Murray and others, 1974; Boyce and Grolier, 1977; Strom, 1977) and the seventh-largest known with the discovery of Skinakas Basin. The west half of the mapped area (between long 100° and 190° W.) is dominated by older craters and by intercrater plains material that lies between and within them. Younger crater materials, intermediate plains material, and small patches of smooth plains material are superposed on all other units. The crater Verdi, 122 km (76 mi) in diameter, is the largest of the younger craters. Its extensive ejecta blanket and secondary crater field are superposed on plains materials and older craters.
The east half of the mapped area (between long 0° and 100° W.) is characterized by smooth plains material (Murray and others, 1974). This unit covers vast expanses of Borealis Planitia, a depression about 1,000 km (620 mi) in diameter that has an irregular arcuate west boundary. This depression is located over the site(s) of one or several old impact structures (Boyce and Grolier, 1977).