Ilha Grande, or "big island", is a 193 km2 (75 sq mi) forested island located around 151 km off of the Atlantic coast of Angra dos Reis, Rio de Janeiro, Brazil, and about 450 km from São Paulo. A popular outdoor destination, the island remains largely undeveloped as much of the area falls within Ilha Grande State Park. Thus, the remainder of the island is subject to stringent development restrictions in order to preserve the natural environment; vehicles are not permitted and roads are virtually non-existent. For visitors, an hour-long, pre-paid boat excursion is the sole way to access the island. Several small villas and hamlets cater to researchers, tourists and nature-lovers, and around 2,000 people inhabit the largest town on the island, Vila do Abraão.

Angra dos Reis is a municipality located in the southern part of the Brazilian state of Rio de Janeiro. The city is located by the sea and includes in its territory many offshore islands, the largest being Ilha Grande.