Río Grande may be considered the heart of the Ona land, known as Onaisin, Karukinka or Yark-Harvin, what means "my land".
In October 1886, an expedition commanded by Julio Popper discovered the river Grande, which was baptized with the name of Juárez Celman in honor of the then president of the Nation.
In 1891 the name was changed by Julio Poper, but due to the popularity of the name Río Grande, used by the people, this last one remained as the official name of the city.
The installation of the first Salesian Mission in 1893 is considered the first record of white people settling in the region. It was founded by Monseñor Fagnano, and works at present as an agrotechnical school.
On July 11 1921 by presidential decree of President Hipólito Irigoyen, Río Grande was recognized as an agricultural colony. It grew very rapidly as a port and center of the estancias.
The first inhabitants came from the area of San Sebastián and settled here at the end of the XIX century. They were workers from the gold mines that ceased to be exploited. Thirty years later, in 1921, Río Grande was officially founded. In 1959 started the oil era that generated a migratory movement complemented by other migrations during the seventies and the eighties with the promulgation of the law of Economic Promotion, that exempted taxes and gave subsidies to industries and settlers.