Rubuta ci gaba don wannan sakin layi - Sojojin Gorkha daga Nepal sun mamaye Darjeeling a cikin 1780s, sun kai hari kan babban birnin Sikkim na Rabdentse, kuma sun haɗu da yankuna har zuwa Kogin Teesta a cikin Nepal. A shekara ta 1816 duk yankin da aka sani da Sikkim na Burtaniya na Nepal ne. Bayan Yaƙin Anglo-Gorkha
, Nepal ta ba da kashi ɗaya bisa uku na yankunanta ga Birtaniyya a ƙarƙashin Yarjejeniyar Sugauli ta 1816, wanda ya haɗa da yankin ƙasa tsakanin Kogin Mechi da Teesta. A ranar 10 ga Fabrairu, 1817, Birtaniyya ta mayar da yankin ƙasa tsakanin Mechi da Teesta zuwa Sikkimese Chogyal a ƙarƙashin Yarjejeniyar Titalia.