Kaithal was previously a part of Karnal District and later, Kurukshetra District until 1st November 1989, when it became the headquarters of the Kaithal District of Haryana. Kaithal shares common boundary with Patiala (Punjab), Kurukshetra, Jind and Karnal.

Kaithal district is situated in the northwest of the Haryana state. Its northwest boundaries which include Guhla-Cheeka is attached to Punjab State.

Kaithal was known as Kapisthal, meaning 'Abode of Kapi'.

In 1767, it fell into the hands of the Sikh leader, Bhai Desu Singh (d. 1781), who led a large Sikh force from his native village of Bhucho, in the Punjab. Bhai Desu's descendants, the Bhai's of Kaithal, ranked among the most powerful Cis-Sutlej states.

The Sikh Rajas of Kaithal, ruled from 1767 until its fall, in 1843. Bhai Udey Singh ruled over Kaithal as the last Raja. Bhai Udey Singh passed away on 14th March 1843.