Antártica Chilena Province is the southernmost of the four provinces in Chile's southernmost region, Magallanes and Antártica Chilena Region (XII). The capital is Puerto Williams. The province comprises the extreme southern part of Isla Grande de Tierra del Fuego, the islands south and west of Isla Grande, and Chile's claims in Antarctica. The province is administratively divided into two communes (comunas): Cabo de Hornos, located at the southern tip of South America, and Antártica, a wedge-shaped claim of Antarctica, which is not internationally recognized. Its total area of 1,265,853.7 km2 (488,749 sq mi) makes it almost twice as large as all other provinces of Chile combined.

The Magallanes Region, officially the Magallanes y la Antártica Chilena Region, is one of Chile's 16 first order administrative divisions. It is the southernmost, largest, and second least populated region of Chile. It comprises four provinces: Última Esperanza, Magallanes, Tierra del Fuego, and Antártica Chilena.