Geothermal drilling is the technical and engineering discipline focused on creating boreholes into the Earth's subsurface to access and utilize geothermal energy resources or for scientific investigation of subterranean heat and geological structures. As a research field, it investigates the methodologies, technological innovations, material science challenges, geological constraints, operational safety protocols, and environmental impacts associated with penetrating high-temperature, high-pressure subsurface environments, critical for advancing sustainable energy production, subsurface exploration, and geological understanding.