Maputo Bay (Baía de Maputo), formerly Delagoa Bay, Baía da Lagoa (in Portuguese) is an inlet of the Indian Ocean on the coast of Mozambique, between 25° 40' and 26° 20' S, with a length from north to south of over 90 km long and 32 km wide.
The bay is the northern termination of the series of lagoons which line the coast from Saint Lucia Bay. The opening is toward the N.E. The southern part of the bay is formed the Machangulo peninsula, which on its inner or western side affords safe anchorage. At its N.W. point is Port Melville. North of the peninsula is Inhaca Island, and beyond it a smaller island, "Ilha dos Portugueses" (The Portugueses' Island), formerly known as Elephant's Island.
In spite of a bar at the entrance and a number of shallows within, Maputo Bay forms a valuable harbour, accessible to large vessels at all seasons of the year. The surrounding country is low and very unhealthy, but the island of Inhaca (Inyak) has a height of 73 m, and is used as a sanatorium. A river 3.7 to 5.5 m deep, known as the Manhissa or Komati, enters the bay at its northern end; several smaller streams, the Matola (from the north), the Umbeluzi (from the west), and the Tembe (from the south), from the Lebombo Mountains, meet towards the middle of the bay in the estuary called by the Portuguese the Espírito Santo, but generally known as the English river; and the Maputo, which has its headwaters in the Drakensberg, enters in the south, as also does the Umfusi river. These rivers are the haunts of the hippopotamus and the crocodile. Humpback whales and several species of dolphins live in the water while Southern right whales and Dugongs were once numerous in the bay and are rare today.
The bay was discovered by the Portuguese navigator António de Campo, one of Vasco da Gama's captains, in 1502. In 1544 the merchant trader Lourenço Marques explored the upper reaches of the estuaries leading into the bay. Subsequently King John III ordered the Bay to be named Baia de Lourenço Marques. Lourenço Marques is reputed to have named the bay Baía da Lagoa (Portuguese: "Bay of the lagoon"). In English the Portuguese "Baia da Lagoa" then was translated and slightly transformed to "Delagoa Bay".
In 1720 the Dutch East India Company built a fort and factory called Lijdzaamheid (Lydsaamheid) on the spot of Lourenço Marques (now Maputo), since April 1721 governed by an Opperhoofd (chief factor), under authority of the Dutch Cape Colony, interrupted by Taylor's pirate occupation from April 1722 to 28 August 1722; in December 1730 the settlement was abandoned. Thereafter the Portuguese had—intermittently—trading stations in the Espírito Santo estuary. These stations were protected by small forts, usually incapable, however, of withstanding attacks by the natives.
In 1823 Captain (afterwards Vice-Admiral) W. F. W. Owen, of the Royal Navy, finding that the Portuguese exercised no jurisdiction south of the settlement of Lourenço Marques, concluded treaties of cession with native chiefs, hoisted the British flag, and appropriated the country from the English river southwards; but when he visited the bay again in 1824 he found that the Portuguese, disregarding the British treaties, had concluded others with the natives, and had endeavoured (unsuccessfully) to take military possession of the country. Captain Owen rehoisted the British flag, but the sovereignty of either power was left undecided till the claims of the Transvaal Republic rendered a solution of the question urgent. In the meantime the United Kingdom had taken no steps to exercise authority on the spot, while the ravages of Zulus confined Portuguese authority to the limits of their fort. In 1835 Boers, under a leader named Orich, had attempted to form a settlement on the bay, which is the natural outlet for the Transvaal; and in 1868 the Transvaal president, Marthinus Pretorius, claimed the country on each side of the Maputa down to the sea. In the following year, however, the Transvaal acknowledged Portugal's sovereignty over the bay.
In 1861, Royal Navy Captain Bickford had declared Inhaca and Elephant islands British territory; an act protested against by the Lisbon authorities. In 1872 the dispute between the United Kingdom and Portugal was submitted to the arbitration of Adolphe Thiers, the French president; and on 19 April 1875 his successor, Marshal MacMahon, declared in favor of the Portuguese. It had been previously agreed by the United Kingdom and Portugal that the right of pre-emption in case of sale or cession should be given to the unsuccessful claimant to the bay. Portuguese authority over the interior was not established until some time after the MacMahon award; nominally the country south of the Manhissa river was ceded to them by the Matshangana chief Umzila in 1861. To honor that decision still one of the in Maputo brewed beers is called "MacMahon" or "2M" (Portuguese: "Dois M"). Also the place at the Maputo railway station, got the name "Praça MacMahon" (MacMahon Square). After Mozambique's independence from Portugal it got a new name: "Praça dos Trabalhadores" (Workers' Square).
In 1889 another dispute arose between Portugal and the United Kingdom in consequence of the seizure by the Portuguese of the railway running from the bay to the Transvaal. This dispute was referred to arbitration, and in 1900 Portugal was found liable and had to pay nearly £1,000,000 in compensation to the shareholders in the railway company.