Alexandra is a town in the Central Otago district of the South Island of New Zealand. It is on the banks of the Clutha River, on State Highway 8, 188 kilometres (117 mi) by road from Dunedin and 33 kilometres (21 mi) south of Cromwell. The nearest towns to Alexandra via state highway 8 are Clyde seven kilometres to the northwest and Roxburgh forty kilometres to the south. State highway 85 also connects Alexandra to Omakau, Lauder, Oturehua, Ranfurly and on to Palmerston on the East Otago coast.

The Clutha River is the second longest river in New Zealand and the longest in the South Island. It flows south-southeast 338 kilometres (210 mi) through Central and South Otago from Lake Wānaka in the Southern Alps to the Pacific Ocean, 75 kilometres (47 mi) south west of Dunedin. It is the highest volume river in New Zealand, and the swiftest, with a catchment of 21,000 square kilometres (8,100 sq mi), discharging a mean flow of 614 cubic metres per second (21,700 cu ft/s). The river is known for its scenery, gold-rush history, and swift turquoise waters. A river conservation group, the Clutha Mata-Au River Parkway Group, is working to establish a regional river parkway, with a trail, along the entire river corridor.