Brunswick Peninsula (Spanish: Península de Brunswick) is a large peninsula in Magallanes y la Antártica Region, Patagonia, Chile, at 53°30′00″S 71°25′00″W﻿ / ﻿53.5°S 71.4166667°W﻿ / -53.5; -71.4166667Coordinates: 53°30′00″S 71°25′00″W﻿ / ﻿53.5°S 71.4166667°W﻿ / -53.5; -71.4166667. It is 16 kilometres (9.9 mi) wide at its base in the north, and almost 80 kilometres (50 mi) in the south. The Strait of Magellan defines the eastern and southern limits while the Otway Sound (Seno Otway) delimits its western shores.