“…The Fold and Thrust Belt was studied extensively in terms of regional geology and tectonics (e.g., Hossain et al, 2019; Khan, 1991; Najman et al, 2012; Reimann, 1993), structures (e.g., Hossain, 1985; Hossain & Akhter, 1983; Hossain et al, 2019; Rahman et al, 1985), and stratigraphy and sedimentology (e.g., Alam et al, 2003; Alam & Ferdous, 1995; Gani & Alam, 1999; Rahman et al, 2017; Sultana & Alam, 2000). Although numerous studies used river longitudinal profile and geomorphic index analyses to understand the feedback between tectonic uplift, erosion, climate, lithology, and deformation in the northern part of the Basin such as the Shillong Plateau, western and eastern syntaxis regions, Lesser Himalayas, and the Siwalik Foreland Basin, the interplay of tectonics and river‐dominated landscape evolution of the Basin is poorly known (e.g., Wobus et al, 2006; Harkins et al, 2007; Aiken & Brierley, 2013; Ambili & Narayana, 2014; Goswami & Pant, 2019; Strong et al, 2019; Topal, 2019; Kothyari et al, 2020; Kumar & Duarah, 2020; Bhattarai et al, 2021, Baruah et al, 2022; Figure 1a). Therefore, the key objective of this paper is to decipher an independent perspective of the rivers' response to the tectonic activity which includes: (i) constraining bedrock river perturbation by analysing stream longitudinal profiles using quantitative morpho‐tectonic analysis of geomorphic metrics, and (ii) mapping and characterizing unmapped geologic lineaments.…”