Sarmiento has today a population of 7200 inhabitants.
Its history started as a key point in a Tehuelche raking, recognized both by Musters and explorer Carlos Moyano in 1880 when they were searching for the route of cattle driving.
The Araucanian or Mapuches, as they are called in their own language, come from the Araucan region, in the centre of Chile. Their massive income to Argentine territory dates from the arrival of Spaniards to Chile in the XVI century. Since they could not be subdued by conquerors, they suffered a violent repression and had to adapt in areas less and less favorable to their way of life, since they were sedentary people devoted to agriculture. They cultivated maize, potatoes, peppers, beans, and marrows. They were metal workers, pot molders, and weavers.
Governor Fontana and his reiflemen met Juan Acosta here in 1884 when he was driving cattle from Río Negro to the Strait of Magellan.
Francisco Pietrobielli, an Italian adventurer and enterpriser arrived to Buenos Aires in 1888, and took part in the construction of the railway joining Madryn and Trelew. When he finished work, he decided to travel around the south of the province, and found in his adventure a valley he called "Valle Ideal" (ideal valley) for its characteristics, and made his way through to Camarones and Rada Tilly.
After some time, he returned with five Welsh families and a Lithuanian one, and formed what would be the first settlement of Colonia Ideal, where they suffered many difficulties.
In 1895 the Club Social de Gaiman requested to the central government the foundation of a colony th the south of the big lakes, and on 21st June 1897, president José Evaristo Uriburu passed decree-law 12.161 to establish the foundation of the so called Colonia Pastorial Sarmiento, with a population formed by 17 different colectivities.
The railroad would join Comodoro Rivadavia and Sarmiento, but the project was cancelled in 1970.
The cultivation of alfalfa was traditional, as well as that of apples and tomatoes.
The valley includes some 42.000 has. distributed approximately in 150 agricultural developments, it is irrigated by the river Senger and an important channelling system.
In Estancia El Relincho, property of Adán García, a close relation was established with the aborigines inhabitants, and they developed the breeding of Creole horses. They were the breeders of the famous horses Gato and Mancha, that joined Buenos Aires and New York with the passionate Swiss rider Tchieffely.