The landmass stretching from southeastern Iran to the east bank of River Sindh in Punjab, and from lower reaches of Helmand in Afghanistan to the Indian Ocean is called Balochistan. It is a semicircle of historically important cities and agricultural areas that stretches from Bandar Abbas on the Persian Gulf through Kerman, the Delta of the Helmand River in Sistan, Kandahar, and Sindh. It is a borderland between India and Iran and a bridge between the Iranian plateau and the Arabian Peninsula. Geographically, in the West, Dasht-e-Lut, Dasht-e-Kavir, and Kerman Mountains separate it from Persia Proper, and the Persian speaking regions of Kerman in the Southeast, Hub River, and Kirther range of Mountains separate it from Sindh. In the Northeast, the right bank of Indus separates it from Pashtunistan and Punjab. In the North, Balochistan is naturally separated from Afghanistan by the natural boundaries of Helmand and the mountain range north of Quetta. In the South, the Indian Ocean separates Balochistan from the Sultanate of Oman.
Historically, Balochistan had a bridging function between the cultures in Mesopotamia and the Iranian highland on the one hand and those in the Indus lowland on the other hand. There are archaeological evidences of overland connections between the early civilizations of the Indus valley and Mesopotamia through Balochistan. From the middle of the first millennium, the area was divided into many provinces of Achaemenid Empire such as Maka (Makuran) and Zaranka (Sistan). The Greeks during the campaigns of Alexander the Great named the southern regions of Balochistan as Gedrosia. During the Sassanid period, the regions which comprised present-day Balochistan were called Turan (Tugran, Turgestan), corresponding to present-day Sarhad, Sarawan and Jhalawan regions, Pradhan (probably modern-day Kharan and Chagai), Makuran, and Sakastan (modern-day Sistan).
Due to the huge influx of migrating Baloch tribes into Balochistan in medieval times, the demographic and political dynamics of the region changed in favor of the Baloch. There began an era of Baloch dominance in the region. Various tribal confederacies of the Baloch became powerful, and one of them established the first Baloch state known as the Khanate of Kalat in mid-seventeenth century. The Khanate was a loose union of the Baloch tribes and survived for nearly three hundred years in an independent or semi-independent status until it was occupied by the British in 1839. After the occupation, Balochistan was divided into many parts.
Present day Balochistan is divided between three states. Western Balochistan is controlled by Iran; Eastern Balochistan is a federating unit of Pakistan while the territory of Nemroz (Eastern Sistan) was incorporated into Afghanistan during the 19th century.