Aneto (pic d'Aneto in French, formerly pic de Néthou) is the highest mountain in the Pyrenees and in Aragon, and Spain's third-highest mountain, reaching a height of . It stands in the Spanish province of Huesca, the northernmost of the three Aragonese provinces, south of the France–Spain border. It forms the southernmost part of the Maladeta massif.
Aneto is located in the Posets-Maladeta Natural Park, in the municipality of Benasque, Huesca province, autonomous community of Aragon, Spain. It is part of the Maladeta massif and is located in the Benasque valley. It consists of Paleozoic terrain of a granitic nature and Mesozoic materials. Its northern side holds the largest glacier in the Pyrenees, covering in 2005; it is shrinking rapidly due to warming summer temperatures and decreasing winter precipitations over the 20th century – it covered 106.7 ha in 1981, and over 200 ha in the 19th century. It is estimated that it has lost more than half of its surface in the last 100 years, and that it may disappear around 2050.
Initially, the mountain did not even have a name. There are indications that the shepherds and hunters from the southern valleys referred to it as Malheta or Malahita or Punta. It was also previously known as La Malahite. The first traveller who is recorded as having seen it from the port (or pass) of Benasque, Louis Ramond de Carbonnières, simply described its appearance as "needles of ice" in 1787.
The highest point of the Pyrenees eventually inherited the name of a village on its south-eastern side: Aneto.
The French, on hearing the Argonese pronunciation of "Aneto", retained the last two clearly accentuated phonetic syllables, "ne" and "tu", ignoring the first syllable "a". Based on such oral transcription, the French name "Netou" came to exist along with several historical variants: Nelto, Nettou, Anetthou, Annetton, Anelthou, Nethom or Aréthon, all used by various cartographers.