The Apennines or Apennine Mountains (/ Ë Ã¦ p Én aÉª n /; Greek: á¼ÏÎ­Î½Î½Î¹Î½Î± á½ÏÎ·; Latin: Appenninus or Apenninus Mons âa singular used in the plural; Italian: Appennini [appenËniËni]) are a mountain range consisting of parallel smaller chains extending c. 1,200 km (750 mi) along the length of peninsular Italy.