Fernelius is a lunar impact crater located in the southern highlands just to the north of the walled plain Stöfler.

[1] The crater Kaiser is located next to the northwest rim of Fernelius.

Southeast of Fernelius is the crater cluster of Miller, Nasireddin, Huggins, and Orontius.

In the past the floor of Fernelius has been resurfaced, leaving a relatively flat, featureless surface with no central peaks.

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