This document provides an overview of geothermal energy, including what it is, where it is located, how it is produced, and its applications. Geothermal energy harnesses heat from within the Earth and can be used directly or to generate electricity. The most active geothermal resources are typically found along tectonic plate boundaries and in areas with volcanism and hot springs. The main uses of geothermal energy are direct use, district heating systems, and electricity generation in power plants.