Polybius 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...

 in the southeast 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 is located to the south-southeast of the larger crater Catharina

Catharina (crater)

Catharina is an ancient lunar impact crater located in the southern highlands. It lies in a rugged stretch of land between the Rupes Altai scarp to the west and Mare Nectaris in the east. To the west-northwest is the crater Tacitus, and the lava-flooded Beaumont lies to the east along the shore of...

, in the area framed by the Rupes Altai

Rupes Altai

Rupes Altai is an escarpment in the lunar surface that is located in the southeastern quadrant of the Moon's near side. It is named for the Altai Mountains in Asia. The selenographic coordinates of this feature are , and it has a length of about 427 km....

 scarp. Some distance to the northeast is the Mare Nectaris

Mare Nectaris

The Sea of Nectar is a small lunar mare or sea located between the Sea of Tranquillity and the Sea of Fecundity . Montes Pyrenaeus borders the mare to the west and the large crater near the south center of the mare is known as Rosse...

, with the flooded craters Beaumont

Beaumont (crater)

Beaumont is a lava-flooded crater located on the southwestern shore of the Mare Nectaris on Earth's Moon. It lies to the northwest of the similarly flooded crater remnant Fracastorius. To the west is the prominent crater Catharina....

 and Fracastorius

Fracastorius (crater)

Fracastorius is the lava-flooded remnant of an ancient lunar impact crater located at the southern edge of Mare Nectaris. To the northwest of this formation lies the crater Beaumont, while to the northeast is Rosse....

.

The crater rim of Polybius appears slightly distended in the northeast, and has a cut through the northern wall. But the wall is otherwise moderately intact with only minor erosion. The interior floor is flat and almost featureless, with no central rise. To the south and east, a ray

Ray system

A ray system comprises radial streaks of fine ejecta thrown out during the formation of an impact crater, looking a bit like many thin spokes coming from the hub of a wheel. The rays can extend for lengths up to several times the diameter of their originating crater, and are often accompanied by...

 from Tycho

Tycho (crater)

Tycho is a prominent lunar impact crater located in the southern lunar highlands, named after the Danish astronomer Tycho Brahe . To the south is the crater Street; to the east is Pictet, and to the north-northeast is Sasserides. The surface around Tycho is replete with craters of various sizes,...

cuts across the bowl-shaped Polybius A and Polybius B craterlets.

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 Polybius.

Polybius	Latitude	Longitude	Diameter
A	23.0° S	28.0° E	17 km
B	25.5° S	25.5° E	12 km
C	22.0° S	23.6° E	29 km
D	26.9° S	27.9° E	9 km
E	24.4° S	26.2° E	9 km
F	22.2° S	23.0° E	21 km
G	22.5° S	22.7° E	5 km
H	21.1° S	22.7° E	8 km
J	22.7° S	23.5° E	9 km
K	24.3° S	25.3° E	14 km
L	22.0° S	28.2° E	7 km
M	21.3° S	22.1° E	6 km
N	23.4° S	26.8° E	13 km
P	21.5° S	22.9° E	17 km
Q	25.1° S	27.5° E	6 km
R	25.6° S	27.3° E	7 km
T	26.1° S	25.5° E	12 km
V	25.2° S	29.1° E	6 km