Hampden is situated beside a broad bay stretching from Aorere Point to Moeraki Point, on a coastal plain which rises westward to the foothills of the Horse Range and the Kakanui Range. The soil of this surrounding plain overlies a limestone formation. The Moeraki Boulders are located two kilometres south of Hampden. Much of the town lies between the Big Kuri (Kurinui) and Little Kuri Creeks.
