Indiscriminate in-channel sand mining leads to serious off-site and onsite impacts on channel morphology and sediment dynamics of rivers. Owing to high sediment flux and the ready availability of gravels and sand, the Himalayan rivers have been exploited for decades. The most observed impacts of in-channel sand mining are channel incision and riverbed coarsening. The former disturbs the equilibrium state of the river, causing erosion downstream, and the latter reduces sediment supply and availability for transport, disrupting longitudinal connectivity. Such effects are now widespread in several Himalayan rivers and considered a major geohazard in this region. Unregulated Sand mining is not just impacting the river channels in terms of channel modifications in the mining stretches but also resulting in cascading effects such as bank erosion, channel incision and flooding in downstream reaches. We provide here a compilation of geomorphic impacts of unregulated sand mining on riverine landscapes that have been documented globally with a special focus on the Himalayan rivers. We have then presented a case study from the Upper Ganga River between Raiwala and Bhogpur in northern India, which has been exploited for gravel and sand for several decades. The Ganga River in this stretch has high sediment flux potential from the tectonically active hinterland, making it suitable for sand mining. We present a hydrogeomorphic approach to study the impact of sand mining on channel morphology and riverine processes of the Upper Ganga River. We use channel belt width, active channel width, and centreline shifts derived from Landsat-based interdecadal planform maps to analyse the impacts on the river channel. We finally present a critical review of the existing sand mining policy in India and some recommendations.