General characteristics
Latitude	8.9° S
Longitude	60.9° W
Diameter	132 km
Depth	2.7 km
Colongitude	300° at sunrise
Name source	Michel F. van Langren

Langrenus is a prominent impact crater located near the eastern lunar limb. The feature is circular in shape, but appears oblong due to foreshortening. It lies on the eastern shore of the Mare Fecunditatis. To the south is the overlapping crater pair Vendelinus and the smaller Lamé.

The inner wall of Langrenus is wide and irregularly terraced, with an average width of about 20 kilometers. The outer ramparts are irregular and hilly, and there is a bright, fragmented ray system spread across the maria to the west. The interior of the crater has a higher albedo than the surroundings, so the crater stands out prominently when the sun is overhead. The crater floor is covered by many boulders, and is slightly irregular in the northwest half. The central peaks rise about a kilometer above the floor.

During the Apollo 8 mission, Astronaut James Lovell described Langrenus as, "quite a huge crater; it's got a central cone to it. The walls of the crater are terraced, about six or seven terraces on the way down."

The Flemish Astronomer Michel Florent van Langren was the first person to draw a lunar map while giving names to many of the features. He even named this crater after himself. Ironically, this is the only one of his named features that has retained his original designation.

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 Langrenus crater.

Many of the more significant associated craters that surround Langrenus have since been renamed by the IAU.

• Langrenus A - See Barkla crater.
• Langrenus B - See Naonobu crater.
• Langrenus C - See Acosta crater.
• Langrenus D - See Al-Marrakushi crater.
• Langrenus F - See Bilharz crater.
• Langrenus J - See Somerville crater.
• Langrenus K - See Atwood crater.