Madeira, officially the Autonomous Region of Madeira, is an autonomous region of Portugal, in the Atlantic Ocean about 805 km (500 miles) southwest of mainland Portugal. Together with the Azores, it's one of the two autonomous regions of Portugal and a special territory of the European Union. It is the southernmost point and region of Portugal.

Madeira is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under 400 kilometres (250 mi) north of the Canary Islands, Spain, 520 kilometres (320 mi) west of Morocco and 805 kilometres (500 mi) southwest of mainland Portugal. Madeira sits on the African Tectonic Plate, but is culturally, politically and ethnically associated with Europe, with its population predominantly descended from Portuguese settlers. Its population was 251,060 in 2021. The capital of Madeira is Funchal, on the main island's south coast.

The archipelago includes the islands of Madeira, Porto Santo, and the Desertas, administered together with the separate archipelago of the Savage Islands. Roughly half of the population lives in Funchal. The region has political and administrative autonomy through the Administrative Political Statute of the Autonomous Region of Madeira provided for in the Portuguese Constitution. The region is an integral part of the European Union as an outermost region. Madeira generally has a mild/moderate subtropical climate with mediterranean summer droughts and winter rain. Many microclimates are found at different elevations.

Madeira, uninhabited at the time, was claimed by Portuguese sailors in the service of Prince Henry the Navigator in 1419 and settled after 1420. The archipelago is the first territorial discovery of the exploratory period of the Age of Discovery.

Madeira is a year-round resort, particularly for Portuguese, British (148,000 visits in 2021), and German tourists (113,000). It is by far the most populous and densely populated Portuguese island. The region is noted for its Madeira wine, flora, and fauna, with its pre-historic laurel forest, classified as a UNESCO World Heritage Site. The destination is certified by EarthCheck. The main harbour in Funchal has long been the leading Portuguese port in cruise ship dockings, an important stopover for Atlantic passenger cruises between Europe, the Caribbean and North Africa. In addition, the International Business Centre of Madeira, also known as the Madeira Free Trade Zone, was established in the 1980s. It includes (mainly tax-related) incentives.

Plutarch in his Parallel Lives (Sertorius, 75 AD) referring to the military commander Quintus Sertorius (d. 72 BC), relates that after his return to Cádiz, he met sailors who spoke of idyllic Atlantic islands: "The islands are said to be two in number separated by a very narrow strait and lie 10,000 furlongs [2,000 km] from Africa. They are called the Isles of the Blessed."

Archaeological evidence suggests that the islands may have been visited by the Vikings sometime between 900 and 1030.

Accounts by Muhammad al-Idrisi state that the Mugharrarin ("the adventurers" – seafarers from Lisbon) came across an island where they found "a huge quantity of sheep, the meat of which was bitter and inedible" before going to the more inhabited Canary Islands, in Spain. This island, possibly Madeira or Hierro, must have been inhabited or previously visited by people for livestock to be present.