Mercurius is a lunar

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 that is located in the northeastern part of the Moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. It lies to the northeast of the smaller crater Carrington

Carrington (crater)

Carrington is a lunar crater that is located just to the northeast of the crater Schumacher, in the northeastern part of the Moon. It lies in a stretch of rough terrain between two small lunar maria, with Lacus Temporis to the northwest and the smaller Lacus Spei to the east...

, and west-northwest of Zeno

Zeno (crater)

Zeno is a lunar impact crater located near the northwestern limb of the Moon. It lies to the east-southeast of the crater Mercurius. Farther to the east of Zeno, along the limb, is the well-formed crater Boss....

. Just to the south is the small lunar mare

Lunar mare

The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...

 named Lacus Spei

Lacus Spei

Lacus Spei is a small lunar mare that is located in the northeastern part of the Moon's near side. To the north is the crater Mercurius and to the west-southwest lies Schumacher....

, and to the west is the larger Lacus Temporis

Lacus Temporis

Lacus Temporis is a small lunar mare that is located in the northeastern quadrant of the Moon's near side. The selenographic coordinates of this feature are , and it lies within a diameter of 117 km....

.

The rim of Mercurius is circular, with a somewhat irregular edge. There are small outward bulges along several sections of the rim, with the most notable bulges being along the eastern and southern sides. The inner wall has slumped around much of the perimeter, producing a sharp edge. The sides are also somewhat worn, with some tiny craterlets overlying the inner wall.

Within the rim the interior floor has been resurfaced by lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

and is nearly level, with a slight hint of a central mound. The remainder of the floor is marked only by a few tiny craterlets and some low ridges in the northeastern corner.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Mercurius.

Mercurius	Latitude	Longitude	Diameter
A	48.0° N	73.6° E	20 km
B	47.4° N	70.0° E	13 km
C	47.5° N	59.4° E	26 km
D	46.1° N	68.6° E	50 km
E	49.7° N	73.3° E	29 km
F	45.2° N	62.9° E	17 km
G	45.1° N	64.3° E	13 km
H	49.2° N	63.6° E	10 km
J	47.2° N	59.0° E	9 km
K	47.4° N	73.2° E	21 km
L	45.9° N	64.3° E	12 km
M	50.9° N	73.9° E	40 km