This study examines the migration and settlement of Muslims in Northeast India, with a particular focus on Assam and its surrounding areas, including Manipur, the Brahmaputra Valley and the Barak–Surma Valley. It tries to explore answers of several key questions: what factors significantly contributed to the expansion of Islam in Northeast India, especially in Assam and Manipur and why did the Sultans of Bengal and the Mughals pursue territorial expansion in such distant regions and what roles did Sufis and Sufism play in these areas? This article highlights the importance of Sufis, merchants, dargahs and shrines in the process of Islamisation in Assam and Manipur during the pre-colonial period. Addressing these questions forms the core of this research article.