The number of forest fires ignitions has decreased worldwide, thus observing increased levels of intensity and destruction, endangering urban areas, and causing material damages and deaths (Portugal - 2017). Forest fire hazard mapping supported by the surveillance strategy targeted at very susceptible areas with high losses’ potential are the common tools to fire prevention. Each Municipality creates its own Forest Fire hazard map, and so it is observed that along the administrative boundary’s discrepancies occur, even when identical types of landuse are in place. With the evolution of geographic information systems technology sustained by the open-source satellite imagery, along with the innovative Habitat Risk Assessment model of the InVEST software allowed the creation of an easily applicable trans-administrative boundary fire hazard map, with frequent update capabilities and fully open source. This work considered three Municipalities (Tomar, Ourém, and Ferreira do Zêzere) which annually observe various forest fire occurrences. Results enabled a homogeneous Forest Fire Risk Map creation, using landuse, slope, road access network, fire ignitions’ history, visualization basins, and the Normalized Difference Vegetation Index (NDVI) as variables. All variables correlate with each other using different weights, in which the different classes of landuse are considered as habitats and the remaining variables as fire hazard stressors. The results produce a coherent monthly updated Risk Map, which is an alternative to many risk assessment systems used worldwide.