The Maerewhenua River, also known as the Marewhenua River, is a small river in the Otago

Otago

Otago is a region of New Zealand in the south of the South Island. The region covers an area of approximately making it the country's second largest region. The population of Otago is...

 region of New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

's South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

. It is located in North Otago

North Otago

The district of North Otago in New Zealand covers the area of Otago between Shag Point and the Waitaki River, and extends inland to the west as far as the village of Omarama . The large east-coast town of Oamaru serves as North Otago's main centre...

 and acts as a tributary of the Waitaki River

Waitaki River

The Waitaki River is a large river in the South Island of New Zealand, some 110 km long. It is the major river of the Mackenzie Basin.It is a braided river which flows through Lake Benmore, Lake Aviemore and Lake Waitaki. These are ultimately fed by three large glacial lakes, Pukaki, Tekapo,...

, which forms the border between Otago and Canterbury

Canterbury, New Zealand

The New Zealand region of Canterbury is mainly composed of the Canterbury Plains and the surrounding mountains. Its main city, Christchurch, hosts the main office of the Christchurch City Council, the Canterbury Regional Council - called Environment Canterbury - and the University of Canterbury.-...

.

The river flows to the east of the small town of Duntroon

Duntroon, New Zealand

Duntroon is a small farming town in the Waitaki District of New Zealand's South Island. Although traditionally considered a North Otago town, it is presently officially located within the farthest southern reaches of Canterbury...

. When the Kurow Branch

Kurow Branch

The Kurow Branch was a branch line railway that formed part of New Zealand's national rail network...

, a branch line

Branch line

A branch line is a secondary railway line which branches off a more important through route, usually a main line. A very short branch line may be called a spur line...

 railway, was under construction in the 1870s, the river posed construction difficulties and the line terminated on the east bank for over five years until a bridge was successfully completed in mid-1881.