Riccius is a lunar impact crater that is located in the rugged, southeastern part of the Moon's near side.

It was named after Italian astronomers Augustinus Riccius and Matteo Ricci.

This formation has been so heavily bombarded by subsequent impacts that it is nearly unrecognizable as a crater.

Only the western and southwestern parts of the rim remains intact, the remainder having been obliterated by small craters.

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Riccius.