Kurdistan Province (Kurdish: پارێزگای کوردستان,, Ostān-e Kordestān) or Kordestan is one of the 31 provinces of Iran. The province of Kurdistan is 28,817 km² in area. It is located in the west of Iran, in Region 3 and bound by Iraq on the west, the province of West Azerbaijan to its north, Zanjan to the northeast, Hamedan to the east and Kermanshah to the south. The capital of Kurdistan Province is the city of Sanandaj (Sinne). Other counties with their major cities are Marivan, Baneh, Saqqez, Qorveh, Piranshahr, Bijar, Kamyaran, Dehgolan, Diwandarreh and Sarvabad.
The mountainous lands of this area first encouraged Iranian-speaking tribes to settle in this region after their immigration to Iran. It was from here where the first plan to overthrow the Assyrian Empire began, leading to their defeat in 612 BCE, and setting the stage for the commence of the Median empire.
During the next few hundred years, the area of present-day Kurdistan Province became the arena of conflict between various invaders, including the Mongols and Timurids. Its steady decline began in the 16th century, when sea traffic replaced the famous Silk Road.
Upon the order of Sultan Muhammad Khodabandeh (Öljaitü), a small town by the name of Soltanabad Chamchal was constructed in Bisotun region to function as the official and political center of Kurdistan in the Middle Ages. It remained the capital for nearly one-and-a-half centuries, until, in 1372 CE, the government moved to Hassanabad fort, 6 km south of Sanandaj (Sinne). Around 14th century, people from Ardalan tribe established themselves in Sinne (Sanandaj) as the rulers of this region.
According to Sharafnama written by Sharaf al-Din Bitlisi, the earliest known leader of the tribe, Bawa Ardalan, was a descendant of Ahmad bin Marwan, who ruled in Diyarbakır. He settled down among the Gorani people in Kurdistan and toward the end of the Mongol period took over the "Şare Zor" (Sharazor) region, where he established himself as an absolute ruler. He is considered to be the founder of the Ardalan principality. The territories of Zardiawa (Karadagh), Khanaqin, Kirkuk, and Kifri, which were already the homelands of the Goran-Kurds, all belonged to this principality. The capital city of the principality was first in Sharazor, but was moved to Sinne later on. During the reign of Shah Ismail I, the founder of Safavid dynasty, Sunni Kurds (among them the Ardalans) were supported by Ottoman against the Shi'ite government of the Safavids. When Soleiman Khan Ardalan came to power in 1630 CE, the throne was transferred to Sanandaj (Sinne), and, from then on, the rulers contributed to the flourishing and development of the area.
The Ardalan Dynasty continued to rule the region until the Qajar monarch Nasser-al-Din Shah (1848-1896) ended their rule in 1867 CE.
The area of Kurdistan Province incorporates portions of the former Gerrus Province.