Demonax is a lunar impact crater near the southern limb of the Moon.

Demonax lies just to the north of the crater Scott, one of the south polar formations.

The southeast rim in particular has a notable collection of impacts, including the satellite crater Demonax A which intrudes into the interior floor.

However, there is a group of central peaks near the midpoint, and the northern part of the floor is rough and hummocky.

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