The Buddhist Kingdom Of Sikkim was a hereditary monarchy from 1642 to 16 May 1975 in the Eastern Himalayas. It was ruled by Chogyals of the Namgyal dynasty.

In 1975, allegations of discrimination against Nepali Hindus in Sikkim led to resentment against the Chogyal. Their instigation led to Indian Army personnel moving into Gangtok. According to Sunanda K. Datta-Ray of The Statesman, the army killed the palace guards and surrounded the palace in April 1975.

After disarming the palace, a referendum on the monarchy was held, in which the Sikkimese people overwhelmingly voted to abolish the monarchy, and the new parliament of Sikkim, led by Kazi Lhendup Dorjee, proposed a bill for Sikkim to become an Indian state, which was promptly accepted by the Government of India.