Wulff Castle, Castle on coastal promontory in Viña del Mar, Chile

Castillo Wulff is a two-story stone-clad building on the coastal edge of Viña del Mar, between the Marga Marga estuary and Caleta Abarca. Its circular turret, added in 1920, stands on rocks on the northern side and is joined to the main house by a short medieval-style bridge. The main entrance was enlarged and an English-style stone structure added in 1946.

Gustavo Wulff, a German saltpeter and coal trader who arrived in Chile in 1881, obtained a special law in 1904 to build on the coast and erected the house in 1905–1906. Architect Alberto Cruz Montt remodelled it from 1917, adding a stone facade and a circular tower linked by a bridge. In 1946 Esperanza de Artaza Matta removed the southern tower. It was declared a National Historic Monument on 20 September 1995.

Gustavo Wulff, a German trader in saltpeter and coal who arrived in Chile in 1881, had the house built as a family residence; the name Castillo Wulff comes from his surname. From 1990 to 1999 it held the Museo de la Cultura del Mar, a collection of objects and texts of the writer Salvador Reyes Figueroa. Since 2005 it has housed the Unidad de Patrimonio of the Viña del Mar municipality and an exhibition hall.

The building now houses the city's Heritage Department and sits at Marina Avenue 37. The site is easy to reach from the coastal road and provides parking and pathways around the rocky promontory.

The tower added around 1920 stands on rocks on the north side of the building and is joined to the main house by a small medieval-style bridge. The structure was commissioned by architect Alberto Cruz Montt, who also covered the house in stone.