This work proposed a base method for automated assessment of Small Hydro-Power (SHP) potential for a run-of-river (RoR) scheme using geographic information systems (GIS). The hydro-power potential (HP) was represented through a comprehensive methodology consisting of a structured raster database. A calibrated and validated hydrological model (Soil and Water Assessment Tool—SWAT) was used to estimate monthly streamflow as the Mesh Sweeping Approach (MSA) driver. The methodology was applied for the upper part of the Huazuntlan River Watershed in Los Tuxtlas Mountains, Mexico. The MSA divided the study area into a rectangular mesh. Then, at every location within the mesh, SHP was obtained. The main components of the MSA as a RoR scheme were the intake, the powerhouse, and the surge tank. The surge tank was located at cells where the hydro-power was calculated and used as a reference to later locate the intake and powerhouse by maximizing the discharge and head. SHP calculation was performed by sweeping under different values of the penstock’s length, and the headrace’s length. The maximum permissible lengths for these two variables represented potential hydro-power generation locations. Results showed that the headrace’s length represented the major contribution for hydro-power potential estimation. Additionally, values of 2000 m and 1500 m for the penstock and the headrace were considered potential thresholds as there is no significant increment in hydro-power after increasing any of these values. The availability of hydro-power on a raster representation has advantages for further hydro-power data analysis and processing.