Monte Fitz Roy (also known as Cerro Chaltén, Cerro Fitz Roy, or simply Mount Fitz Roy) is a mountain in Patagonia, on the border between Argentina and Chile. It is located in the Southern Patagonian Ice Field, near El Chaltén village and Viedma Lake. It was first climbed in 1952 by French alpinists Lionel Terray and .
The first Europeans recorded as seeing Mount Fitz Roy were the Spanish explorer Antonio de Viedma and his companions, who reached the shores of Viedma Lake in 1783. Argentine explorer Francisco Moreno saw the mountain on 2 March 1877; he named it Fitz Roy in honour of Robert FitzRoy who, as captain of , had travelled up the Santa Cruz River in 1834 and charted large parts of the Patagonian coast.
Cerro is a Spanish word meaning ridge or hill, while Chaltén comes from a Tehuelche (Aonikenk) word meaning "smoking mountain", because a cloud usually forms around the mountain's peak. Fitz Roy is one of several peaks the Tehuelche called Chaltén.
Argentina and Chile have agreed that their international border detours eastwards to pass over the main summit, but a large part of the border to the south of the summit, as far as Cerro Murallón, remains undefined. The mountain is the symbol of the Argentine Santa Cruz Province, which includes its representation on its flag and its coat of arms.
On February 27, 2014, Chile's National Forestry Corporation created the Chaltén Mountain Range Natural Site by Resolution No. 74, which covers the Chilean side of Mount Fitz Roy and the surrounding mountain range.
After the signing of the 1881 Treaty between Argentina and Chile, the boundary in the area was defined in 1898 by the boundary surveyors, Francisco Pascasio Moreno from Argentina and Diego Barros Arana from Chile. Huemul was declared a border landmark. The surveyors had no differences in the area between Mount Fitz Roy and Cerro Stokes, unlike other territories that were subject to arbitration in the 1902 arbitral award. The boundary was defined by the following mountain landmarks and their natural continuity: Mount Fitz Roy, Torre, Huemul, Campana, Agassiz, Heim, Mayo, and Stokes (nowadays Cervantes). Chile has defended it as a border landmark.
In 1998, the "Agreement between the Republic of Chile and the Republic of Argentina to determine the boundary line from Mount Fitz Roy to Cerro Daudet" was signed, defining section A and a small part of section B, with the area between Fitz Roy and the Murallón still pending.
Fitz Roy is a popular tourist destination for hikers, as a viewpoint between the Laguna de Los Tres and the Laguna Sucia can be reached by foot from the town of El Chaltén. The total trek is around 20 kilometers for the round trip, making it possible to do the out-and-back hike within a single day, while also passing by the Poincenot campground that is run by a local association, for people who want to take more time.