This repository contains the VIC-Res model for the Mekong River Basin (including both runoff generation and streamflow routing components) along with input and output datasets. Updates in This Release This release includes updated reservoir parameter files for the Mekong routing network. The updates include: 1) addition of new reservoirs to the routing system, 2) updates to reservoir storage and operational parameters; 3) revised reservoir operation strategies for improved representation of reservoir regulation. These changes improve the representation of reservoir operations and water management infrastructure in the Mekong River Basin model. This version (v2.1.1) updates the reservoir parameterization file by incorporating the actual operational start year for each reservoir. In contrast to v2.1, which assumed a uniform start year of 1950 for all dams, this revision improves the temporal realism of reservoir representation within the model. Minor updates were made to the VIC-Res routing model to improve compatibility with VIC4.2 and VIC5 workflows, including support for reading grid latitude and longitude from input files. For more information on the model structure, usage, and implementation, please visit: https://github.com/Critical-Infrastructure-Systems-Lab/VICResNote that the updated version released here includes new and revised reservoir parameters, and has not yet been recalibrated. Calibration and validation of the updated version are currently in progress. Version 2.0 also includes the scripts required for model calibration, allowing users to perform the calibration if needed. In addition, the calibration files from the previous version are provided and may still be used if desired. This work is published in Environmental Modelling & Software: Eldardiry, H., Mahto, S. S., Fatichi, S., & Galelli, S. (2025). VIC-Res Mekong: An open-source hydrological-water management model for the Mekong River Basin. Environmental Modelling & Software.