Few words About Darjeeling

Were Darjeeling and Kalimpong historically a part of Bengal?
No. Darjeeling was a dominion of Chogyal of Sikkim and was overrun by Nepal in 1780.
The region was annexed by the British during the 1814 Anglo-Nepal War and was ceded by Nepal to British India in the Sugauli Treaty of 1815.
Kalimpong was a part of Bhutan and was ceded to the British in the Sinchula Treaty of 1865 after the 1864 Anglo-Bhutan War. The present Darjeeling district as part of Bengal came into being in 1866.
However, administratively it was classified as a ‘Non-regulated area’ before 1861 and 1870-74 and as ‘Regulated area’ between 1862 and 1870. It was termed as ‘Scheduled district’ in 1874, as ‘Backward Tracts’ in 1919 and ‘Partially-excluded area’ from 1935 till 1947.