Brunswick Peninsula (Spanish: Península de Brunswick) is a large peninsula in Magallanes y la Antártica Region, Patagonia, Chile, at (53.5°S 71.4166667°W). It is 16 kilometres (9.9 mi) wide at its base in the north, and almost 80 kilometres (50 mi) in the south. It measures 115 kilometres (71 mi) in length from the base to Cape Froward, the southernmost point of the American mainland.