The Pitcairn Islands, officially Pitcairn, Henderson, Ducie and Oeno Islands, are a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territory in the Pacific Ocean. The four islands—Pitcairn, Henderson, Ducie and Oeno—are scattered across several hundred miles of ocean and have a combined land area of about 18 square miles (47 km2). Henderson Island accounts for 86% of the land area, but only Pitcairn Island is inhabited. The inhabited islands nearest to the Pitcairn Islands are Mangareva, 688 km to the west, as well as Easter Island, 1,929 km to the east.

The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east.