Today's county of Cluj has witnessed mankind evolution since early times. A remarkable progress took place during the Neolithic era; archaeological findings throughout the county of Cluj are a proof thereof. Thus, the oldest Neolithic remains known to us so far throughout Romania were found at Gura Baciului. The Roman conquest of Dacia opened a new stage in the evolution of the human society living here. The continuity of the Dacian-Roman population during the 4th and 5th centuries is proved by the presence of the central graveyard on Plugarilor street, dating back to the 4th century. Many migratory peoples settled in the area of the county besides the Dacian-Roman population. The treasures found at Apahida and Cimpia Turzii are illustrative in this respect. In mediaeval times, the local Transylvanian principality centered in Alba Iulia founded two counties of the seven that existed in the province of Transylvania at the time. These were the county of Dabaca, mentioned in historical records in 1164, and the county of Cluj, first mentioned in 1177. The latter had branched off the former county of Alba. Centuries 13th through 14th witness an accelerated development of feudalism in the county of Cluj.

The royal house supported feudal authorities in the county. These were the local administrative and political unit including the county of Cluj and three other counties: the county of Dabaca, centered in Dabaca, the county of Turda centered in Turda, and the county of Solnocul Inferior centered in Dej. The city of Cluj was revigorated thanks to the population gathered around the Roman camp at Cluj-Manastur and the village built over the ancient city of Napoca and the monastery that had been erected here during the 12th century. The city of Cluj undergoes a time of flourishing in the 16th century, when rich trade businesses took shape. The city also hosted the capital of the homonymous county.

Mediaeval Turda was reborn in the vicinity of the ancient city of Potaissa. An important contribution therein belonged to the salt mines in the area, mentioned in historical records in 1075. Dej is a city founded in the Middle Ages at the confluence of the rivers Somesul Mic and Somesul Mare. During the autonomy of the principality of Transylvania under Turkish suzerainty, although the principality's capital was in Alba-Iulia, Cluj remained the most important city from the economic, political and cultural viewpoints. At the end of the 17th century, Transylvania was conquered by the Habsburgs, and the principality was included in the Habsburg Empire. The end of the 18th and the beginning of the 19th century mark the end of the mediaeval era and the dawn of capitalism. After the revolution of 1848, the capitalist development of Cluj takes up speed. In 1918, after battles fought by the masses oppressed both socially and nationally, the Austro-Hungarian Empire collapsed and Transylvania was reunited with the other Romanian provinces. The freeing of northern Transylvania and its reintegration within Romanian borders was determined by the signing of the respective political document on August 23, 1944, in Bucharest. Cluj was freed on October 11, 1944, by Soviet and Romanian troops. During all this time, Cluj had remained one of the most important cities in the country. It was the political and administrative centre of the region, and starting in 1968 it is also the capital of the homonymous county.