This is a reconstructed monthly streamflow for 1951-2021 period for the Indian sub-continental river basins. We used a high-resolution vector-based routing model (mizuRoute) to generate streamflow at 9579 stream reaches in the sub-continental river basins. The resulting dataset provides valuable insights into the observed streamflow variations in the Indian subcontinental river basins, aiding hydrological research, water resource management, and understanding the impacts of climate change on regional river systems.