Pelješac is well known by some of the best Croatian vino. The major grape is Plavac Mali, the foundation of many highly-regarded Dalmatian red wines, such as from the region of Postup and Dingač.
an excellent article packed with information:
More about Pelješac at Wikipedia http://en.wikipedia.org/wiki/Pelješac
Pelješac (local Chakavian dialect: Pelišac; Italian: Sabbioncello) is a peninsula in southern Dalmatia in Croatia. The peninsula is part of the Dubrovnik-Neretva County and is the second largest peninsula in Croatia. From the isthmus that begins at Ston, to the top of Cape Lovišta, it is 65 km long. The name ‘Pelješac’ is most likely derived from the name of a hill above town of Orebić, which is Pelisac. This is a relatively new name for the peninsula. Throughout history other names have been used such as Stonski Rat, Puncta Stagni, Ponta di Stagno and Sabioncello. The main town of Peljesac is Ston which has large fortifications, built by the Republic of Ragusa(Dubrovnik). They are the second longest walls in Europe and perhaps one of the oldest salt planes in this part of the world.