History of Kullu District also suggests the origin of its name. It says that Kullu derives its name from 'Kalut' which was a tribe in the upper valley of River Beas, as mentioned by Barahmir in Barihat Sahinta. There are other evidences in history and literature that confirm that the name of this part was 'Kalut' and the letter 'T' was eventually dropped from the name with the passage of time. Thus, this place got its present name Kullu.
Further, history of Kullu District comprises two phases - pre independence and post independence period. History of the district of the pre-independence period states that Kullu was probably the most ancient state next to Kashmir and Kangra. According to historical accounts, it was founded in the first century of Christian era by Behangamani Pal. Many legends are associated with the name of Behangamani Pal. It appears that the people of the higher valley of Kullu at that time were suffering under the repressive regime of the Thankurs of Spiti. Behangamani Pal organised the upper valley first revolution sparked off at Jagatsukh. Subsequently, Pal dynasty was thus established. Its original capital was established at Jagatsukh and nearly ten generations ruled from there, till it was shifted to Naggar which remained as the seat of the Government for many as 1400 years till it was finally moved to Kullu.
Their rule continued till about 1,450 when reference is available of Raja Kelas Pal. After this, there was long break of about 50 years. It appears the Thakurs and the Ranas might have captured power during this period, forcing the Pal Rajas to flee from the valley. It was again in the fifteenth century that the name of the Sidh Singh appears as the Raja of Kullu. He too helped the people in organizing rallies against the Thakurs and established the old Pal dynasty. Reference may be made to Raja Jagat Singh (1637-1672) who conquered the fort the Madankot which belonged to Jihna Rana, above Manali. It was during his regime that the famous idol of Raghunathji was brought from Ayodhya and installed at the temple of Raghunathji at Sultanpur (Kullu).
History of Kullu District says that after the independence of the country, like other hill states, Kullu had its ups and downs till it was ceded to the British in 1846 as per Lahore agreement, along with other trans-Sutlej states. Firstly, Kullu was made a sub-division of the district of Kangra. Lahul-Spiti was made a part of Kullu for proper administration. In the year 1960, Lahul-Spiti was declared a separate district. In the year 1963, Kullu was also made a separate district and it remained a part of Punjab till October 1966. After the reorganization of states, Kullu District was made a part of Himachal Pradesh on 1st of November, 1966.