North Sentinel Island is one of the Andaman Islands, an Indian archipelago in the Bay of Bengal which also includes South Sentinel Island. The island is a protected area of India. It is home to the Sentinelese, an indigenous tribe in voluntary isolation who have defended, often by force, their protected isolation from the outside world. The island is about eight kilometres (five miles) long and seven kilometres (4+1⁄2 miles) wide, and its area is approximately 60 square kilometres (23 sq mi).

The Andaman and Nicobar Islands Protection of Aboriginal Tribes Regulation 1956 prohibits travel to the island and any approach closer than five nautical miles (nine kilometres), in order to protect the remaining tribal community from "mainland" infectious diseases against which they likely have no acquired immunity. The area is patrolled by the Indian Navy.

Nominally, the island belongs to the South Andaman administrative district, part of the Indian union territory of Andaman and Nicobar Islands. In practice, Indian authorities recognise the islanders' desire to be left alone, restricting outsiders to remote monitoring (by boat and sometimes air) from a reasonably safe distance; the Government of India will not prosecute the Sentinelese for killing people in the event that an outsider ventures ashore. In 2018, the Government of India excluded 29 islands—including North Sentinel—from the Restricted Area Permit (RAP) regime, in a major effort to boost tourism. In November 2018, the government's home ministry stated that the relaxation of the prohibition on visitations was intended to allow researchers and anthropologists (with pre-approved clearance) to finally visit the Sentinel islands.

The Sentinelese have repeatedly attacked approaching vessels, whether the boats were intentionally visiting the island or simply ran aground on the surrounding coral reef. The islanders have been observed shooting arrows at boats, as well as at low-flying helicopters. Such attacks have resulted in injury and death. In 2006, islanders killed two fishermen whose boat had drifted ashore, and in 2018 an American Christian missionary, 26-year-old John Chau, was killed after he illegally attempted to make contact with the islanders three separate times and paid local fishermen to transport him to the island.