Montes Apenninus are a rugged mountain range on the northern part of the Moon’s near side. They are named after the Apennine Mountains in Italy.
This range forms the southeastern border of the large Mare Imbrium lunar mare and the northwestern border of the Terra Nivium highland region. It begins just to the west of the prominent crater Eratosthenes, which abuts against the southern face of the range. To the west of these mountains is a narrow gap where Mare Imbrium in the north joins Mare Insularum to the south. Further to the west are the Montes Carpatus mountains.
From Eratosthenes, the mountains form an arcing chain that gradually bends from east to northeast, ending at Promontorium Fresnel at about latitude 29.5° N. Here is another gap where the Mare Imbrium to the west joins the Mare Serenitatis to the east. At the north end of this gap lie the Montes Caucasus.