Si Thep is on a dry highland surrounded by waterways and floodplains bordered by mountains on both sides. To ensure sufficient water for city use, ancient Si Thep had an elaborate system of ponds, tank moats, and a hydraulic system to bring water from higher grounds to sustain the city. Neighboring districts are (from the north clockwise)
Wichian Buri of Phetchabun Province, and
Lam Sonthi,
Chai Badan, and
Khok Charoen of
Lopburi province. ==Administration==