Pegasus Bay is on the east coast of the 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...

 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...

.

Location

The bay has a sandy beach and runs from Banks Peninsula

Banks Peninsula

Banks Peninsula is a peninsula of volcanic origin on the east coast of the South Island of New Zealand. It has an area of approximately and encompasses two large harbours and many smaller bays and coves...

 to the Waipara River

Waipara River

The Waipara River is a river the South Island of New Zealand.The river passes through the small town of Waipara on its 45 kilometre southeastward journey to the Pacific Ocean at the Northern end of Pegasus Bay....

 mouth. The city of Christchurch

Christchurch

Christchurch is the largest city in the South Island of New Zealand, and the country's second-largest urban area after Auckland. It lies one third of the way down the South Island's east coast, just north of Banks Peninsula which itself, since 2006, lies within the formal limits of...

 is at the southern end of the bay.

Rivers

Rivers flowing into Pegasus Bay, from north to south, are:

• Waipara River
• Ashley River
  Ashley River, New Zealand
  The Ashley River is located in Canterbury Region of New Zealand. It flows generally southeastwards for 65 kilometres before entering the Pacific Ocean at Waikuku Beach, Pegasus Bay north of Christchurch. The town of Rangiora is close to the south bank of the Ashley River...
  
  
• Waimakariri River
  Waimakariri River
  The Waimakariri River is the largest of the North Canterbury rivers, in the South Island of New Zealand. It flows for 151 kilometres in a generally southeastward direction from the Southern Alps across the Canterbury Plains to the Pacific Ocean....
  
  
• Avon River
  Avon River, Canterbury
  The Avon River flows through the centre of the city of Christchurch, New Zealand, and out to an estuary, which it shares with the Heathcote River, the Avon Heathcote Estuary.- Geology :...
  
   and Heathcote River
  Heathcote River
  The Heathcote River lies within the city boundaries of Christchurch, New Zealand, and is fed from springs near Templetons Road and also receives wet weather flows from as far west as Pound Road. It meanders around the base of the Port Hills from west to south-east.-Course:The catchment of the...
  
   via the Avon Heathcote Estuary
  Avon Heathcote Estuary
  The Avon Heathcote Estuary is the largest semi-enclosed shallow estuary in Canterbury and remains one of New Zealand’s most important coastal wetlands. It is well known as an internationally important habitat for migratory birds, and it is an important recreational playground and educational resource...
  
  

Naming

The Pegasus was the name of the sailing ship which surveyed part of the South Island in 1809. The first mate of the brig

Brig

A brig is a sailing vessel with two square-rigged masts. During the Age of Sail, brigs were seen as fast and manoeuvrable and were used as both naval warships and merchant vessels. They were especially popular in the 18th and early 19th centuries...

 Pegasus, William Stewart, gave Pegasus Bay its name. The captain of the ship, Captain Samuel Chase (not to be confused with his contemporary, Captain Samuel Rodman Chace), lays claim to correcting James Cook

James Cook

Captain James Cook, FRS, RN was a British explorer, navigator and cartographer who ultimately rose to the rank of captain in the Royal Navy...

's charts by determining that "Banks Island" was in fact a peninsula.