<p>Northeast India is a tectonically complex region exhibiting the collision between the Indo-Eurasian tectonic plates to the north and subduction between the Indo-Burma plate along its eastern periphery. This study incorporated twenty permanent and three temporary broadband seismic stations’ ambient noise data to decipher the region's crustal structure. We cross-correlate ambient noise records to retrieve group velocity maps for periods ranging from 6 to 25&#xa0;s. With the help of short-period tomograms (&lt; 10&#xa0;s), we identify the contact between the undifferentiated granites and Eocene rocks on the Shillong plateau, as well as major geomorphological features of the Bengal basin, Indo-Burma ranges, and the Brahmaputra River valley. For long periods (&gt; 10&#xa0;s), our results reveal that the basement rocks of the Shillong massif are separated from the sediments of the Bengal basin by a northwardly dipping Dauki thrust fault. The dip of the Dauki fault is constant up to ~ 16&#xa0;s, and it becomes steeper towards north at higher depths. Our group velocity maps suggest that the tectonic stresses may be responsible for the uplift and expansion of the Shillong massif. Furthermore, the crustal thickness of the Bengal basin increases gradationally towards its eastern boundary, indicating the occurrence of oblique subduction at the Indo-Burmese arc. Again, the 25⁰ latitude differentiates slower and faster velocities in the Indo-Burma region from north to south, which aligns with the thicker crust in the southern region of the Indo-Burma ranges.</p>