Delagoa Bay, a Portuguese possession, is a large inlet of the Indian Ocean on the south-east coast of Africa. Discovered by one of Vasco da Gama's lieutenants in 1502, it was called Bahia da Lagoa, from a rumoured great lake in the interior. Negotiations for the sale or cession of it to Britain have always been rejected by the Portuguese. In 1868 the Transvaal claimed by proclamation the Maputa River, from its junction with the Pongola to its embouchure into the southern part of Delagoa Bay. England and Portugal resisted the claim and set up counter pretensions. The matter was referred to the arbitration of Marshal MacMahon, who in 1875 declared the southern portion of Delagoa Bay, including the Maputa River up to the Lobombo Mountains, to belong to Portugal. The bay stretches for 70 miles between and S. lat. It is 25 miles wide, and for size and accommodation is the finest natural harbour in South Africa; in spite of islands and shoals its navigation is safe and easy, and the anchorage is commodious and well sheltered. The settlement of Lourenço Marques and surrounding country have been notoriously unhealthy; but of late years some drainage and other improvements have been carried out. The rivers Maputa, Tembe, and Umbelosi (joining to form the English River), and the Komati, fall into Delagoa Bay. The proximity of Delagoa Bay to the Transvaal goldfields greatly increased its commercial and political importance. For over half a century there were intermittent attempts to establish communication between the Transvaal and Delagoa Bay. All failed till 1887, when a company was formed in London to work a concession from the Portuguese government for ninety years, for the construction of a railway from Delagoa Bay to the Transvaal (52 miles); but in 1889—through intrigues by the Transvaal—the Portuguese government expropriated the company (largely Englishmen and Americans). An international arbitration was soon thereafter arranged, which did not report till 1900, when Portugal was adjudicated to pay £641,000, to the grievous disappointment of the concessionaires, who had demanded over £1,500,000. The lines connecting with Pretoria (350 miles by rail from the coast) and with Johannesburg, &c., were completed in 1890-95, and both before and during the war of 1899-1900 proved invaluable to the Transvaal.
See LOURENÇO MARQUES, and works by Monteiro (1891) and Montague (1899).