Alden is a lunar crater that lies on the far side of the Moon, between Hilbert to the north-northwest and Milne to the south-southeast. To the south-southwest lies Scaliger. Alden has a low rim that is overlain in the north and northeast by Alden C and the smaller Alden E. The rim is worn and eroded, especially along the southern wall. The floor is somewhat irregular and pitted. The small crater Alden V lies just inside the north rim, and is attached to Alden C to the east.