Mare Frigoris 56.0°N, 1.4°E

Whereas the other maria show a tendency towards a nearly circular shape, Mare Frigoris (‘Sea of Cold’) is elongated and lies in the Moon's northern polar region. It stretches about 300 km in a northsouth direction, but over 1000 km in an east-west direction. The areas of Lacus Mortis and Sinus Roris form part of it. It covers an area of about 440 000 km2 and is approximately comparable with the area of the Black Sea on Earth.

J. Herschel 62.0°N, 42.0°W

The remnant of a giant crater, 165 km in diameter. The crater floor is covered in rubble from the Imbrium impact. In larger telescopes and under grazing illumination the rough nature of the rubble is clearly visible.

There are three craters on the Moon's nearside that are named after members of the Herschel family. J. (John) was the son of William Herschel (the crater Herschel north of Ptolemaeus) and C. (Caroline) Herschel, his sister (the crater in Mare Imbrium).

Harpalus 52.6°N, 43.4°W

A prominent, young crater with a sharp crater wall, 39 km in diameter, lying on the lava surface of Mare Frigoris. The crater's floor appears rough and furrowed. Under high illumination the crater exhibits a ray system. To the west lie a few smaller, low, isolated ridges.

Horrebow 58.7°N, 40.8°W

A small crater, 24 km in diameter, which overlays Horrebow A (25 km) to the northeast. Both craters lie on the southern crater wall of J. Herschel. Together, Horrebow and Horrebow A appear rather pear-shaped, like the crater Torricelli.