The Happy Valley Reservoir is a water reservoir located in the southern Adelaide suburb of Happy Valley, South Australia. Constructed when the total population of Adelaide numbered 315,200, the Happy Valley Reservoir now supplies over half a million people, from Adelaide's southern extent to the city centre. The surrounding area is home to much wildlife, including many kangaroos.

Adelaide is the capital and largest city of South Australia, and the fifth-most populous city in Australia. "Adelaide" may refer to either Greater Adelaide or the Adelaide city centre. The demonym Adelaidean is used to denote the city and the residents of Adelaide. The traditional owners of the Adelaide region are the Kaurna. The area of the city centre and surrounding Park Lands is called Tarndanya in the Kaurna language.