Geminus is a lunar impact crater that is located near the northeast limb of the visible Moon.

The crater ejecta is still visible in the rough surroundings beyond the rim, but any rays deposited during the impact have long since been worn away by space weathering.

There are no notable impacts on the interior floor, but there is a long, slender central ridge located at the midpoint and a pair of readily observed clefts.

Notable nearby craters include Messala to the northeast, Bernoulli due east, and Burckhardt and Cleomedes to the south.

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