The magmatic processes that affected the Tyrrhenian sector of the Italian peninsula in the Pliocene and Quaternary are responsible for the conspicuous thermal anomaly, highlighted by the high surface heat flux and by the rapid increase in temperature with depth. Furthermore, the local geology has often allowed the formation and persistence of important hydrothermal geothermal systems, potentially exploitable for the production of electricity or for direct heating. This paper deals with the situation in the Viterbo area, where the geothermal systems of Latera and Torre Alfina werem discovered decades ago. The analysis of the rich documentation contained in the inventory of Italian geothermal resources has made it possible to evaluate the geothermal potential of each municipality in the Viterbo province (Provincia di Viterbo), in order to plan further research aimed at identifying and exploiting geothermal reservoirs, in compliance with the environmental protection and resource sustainability.