Amapá (Portuguese pronunciation: [amaˈpa]) is one of the states of Brazil, located in the extreme north, bordering French Guiana and Suriname to the north. To the east is the Atlantic Ocean, and to the south and west is the Brazilian state of Pará. The estuary of the River Oiapoque, once considered the northernmost point of Brazil, is at the extreme north of the Brazilian coast. The dominant feature of the region—90 percent of the total area—is the Amazon Rainforest. Unexplored forests occupy 70 percent of its territory. The state's capital and largest city Macapá can only be reached by boat or airplane.

As the "Capitania" of Costa do Cabo Norte, the region was invaded by the English and Dutch, who were repelled by the Portuguese. The Treaty of Utrecht in 1713 established the boundaries between Brazil and French Guiana, but these were not respected by the French. In the 18th century, France retook control of the area. This dispute would continue until 1900.

With the discovery of gold and the increasing value of rubber on the international market during the 19th century, which led to population increases in Amapá, the territorial dispute with France was brought to a head; finally, on December 1, 1900, the Arbitration Commission of Geneva ceded possession of the territory to Brazil, which incorporated it into the state of Pará with the joint name of Araguari (named for the river of the same name). It became the federal territory of Amapá in 1943.