Ritter 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...

 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...

 located near the southwestern edge of Mare Tranquillitatis

Mare Tranquillitatis

Mare Tranquillitatis is a lunar mare that sits within the Tranquillitatis basin on the Moon. The mare material within the basin consists of basalt formed in the intermediate to young age group of the Upper Imbrian epoch. The surrounding mountains are thought to be of the Lower Imbrian epoch, but...

. It is the northwestern member of a crater pair with Sabine

Sabine (crater)

Sabine is a lunar crater that forms a nearly matching pair with Ritter to the northwest. The two rims are separated by a distance of only a couple of kilometers. To the west is the bowl-shaped crater Schmidt, and farther to the north are Manners and Arago....

 to the southeast. The two rims are separated by a narrow valley only a couple of kilometers wide. To the northwest is the crater Dionysius

Dionysius (crater)

Dionysius is a lunar impact crater that lies on the western edge of the Mare Tranquillitatis. To the southeast is the crater pair of Ritter and Sabine. Just to the northwest is the system of rilles designated Rimae Ritter. These clefts follow a generally northwest direction.The rim of Dionysius is...

, and to the north-northeast are Manners

Manners (crater)

Manners is a lunar impact crater located in the western part of the Mare Tranquillitatis. To the northeast is the larger crater Arago, and to the south are Ritter and Sabine. The crater has a rim with a higher albedo than the surrounding mare, making it appear bright...

 and Arago

Arago (lunar crater)

Arago is a lunar impact crater located in the western part of the Mare Tranquillitatis. To the southwest lies the crater Manners, and beyond are Dionysius and the Ritter–Sabine crater pair. To the southeast is the large Lamont formation that has been submerged by the mare.The rim of Arago has a...

. This crater is roughly circular but with an irregular outer rim. The inner walls have slumped down towards the floor. The interior is irregular with several low ridges. To the northwest of Ritter is a system of parallel rille

Rille

Rille is typically used to describe any of the long, narrow depressions in the lunar surface that resemble channels. Typically a rille can be up to several kilometers wide and hundreds of kilometers in length...

s designated Rimae Ritter. These follow a course to the northwest.

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 Ritter.

Ritter	Latitude	Longitude	Diameter
B	3.3° N	18.9° E	14 km
C	2.8° N	18.9° E	14 km
D	3.7° N	18.8° E	7 km