The History of Ilha Grande

Indigenous origins

Long before European ships arrived, the island was inhabited by the Tupinambá, part of the Tupi-Guarani peoples who lived along this stretch of coast. They called the surrounding waters home and left shell mounds (sambaquis) and place names that survive today. Portuguese navigators reached the bay in the early 16th century, and the island appeared on maps as a strategic point on the route between Rio de Janeiro and São Paulo.

Pirates and smugglers

For centuries the sheltered coves of Ilha Grande were a haven for pirates, corsairs and smugglers. The island’s hidden bays made it a natural base for contraband — first gold and later, along this coast, enslaved people brought in illegally after the transatlantic slave trade was outlawed. Local legends of buried treasure still cling to beaches like Saco do Céu and Lagoa Azul.

The Lazareto quarantine station

In 1886 the imperial government built the Lazareto, a quarantine station near Vila do Abraão where arriving immigrants were held and inspected for diseases such as cholera before being allowed onto the mainland. Its imposing stone buildings and the aqueduct that supplied them still stand as ruins today, reachable on an easy walk from Abraão and now slowly reclaimed by the forest.

The prison island

The Lazareto later became a prison, and in the 20th century Ilha Grande gained its most notorious institution: the Cândido Mendes penal colony at Dois Rios, on the island’s open ocean side. During the military dictatorship it held both common criminals and political prisoners, and it is often cited as one of the places where the ideas behind Rio’s Comando Vermelho took shape. The prison was closed and demolished in 1994.

From prison to protected paradise

The very isolation that made the island a prison also protected its nature. With the penal colony gone, Ilha Grande was given over to conservation. Most of it is now the Ilha Grande State Park (Parque Estadual da Ilha Grande) and other protected areas, safeguarding Atlantic rainforest, rare wildlife and dozens of pristine beaches. In 2019, Ilha Grande — together with the historic town of Paraty — was inscribed as a mixed UNESCO World Heritage Site, recognized for both its culture and its biodiversity.

Walking the island today, you can still trace this layered past: the aqueduct and Lazareto ruins near Abraão, the old prison site and small museum at Dois Rios, and the forest that has grown back over it all.