Aliacensis is a lunar impact crater that is located in the rugged southern highlands of the Moon.

The crater Werner is located just to its north-northwest, and a narrow, rugged valley lies between the two comparably sized formations.

Aliacensis is named after the 14th century French geographer and theologian Pierre d'Ailly in 1935.

The interior floor is generally flat, with a low central peak slightly offset to the northwest of the midpoint.

[2][4] By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Aliacensis.