Gazelle Peninsula,peninsula extending northeast from the island ofNew Britain,Papua New Guinea, southwesternPacific Ocean. It is about 50 miles (80 km) wide buttapers to 20 miles (32 km) at the isthmus that joins it to the main part of the island. From coastal plains its surface rises as high as 7,999 feet (2,438 metres) at Mount Sinewit in the central Baining Mountains. Simpson (Rabaul) Harbour, near the northern tip of the peninsula, is one of the best natural harbours in the South Pacific. The area is actively volcanic and therefore highly fertile.

The peninsula is the most-populous portion of the island (particularly on the east). It was there that theGermans established their centre of settlement during their colonization of Papua New Guinea in the 19th century. Many copra and cocoa plantations along the coast ship their produce through the ports ofRabaul and Kokopo on Blanche Bay. Those settlements are served by secondary roads. A volcanological observatory is located in Rabaul, a town situated in a region of particularly intensevolcanic activity. Vulcan Crater, at the tip of the peninsula, erupted twice during the 20th century: in 1937 and, simultaneously with nearbyMount Tavurvur, in 1994. The eruptions caused severe damage to Rabaul and the surrounding area. Tavurvur and Vulcan continued to erupt every few years in the early 21st century.