Both Viedma, the capital of the province of Río Negro, and Carmen de Patagones in the province of Buenos Aires have a common origin, when the fort and village Nuestra Señora del Carmen were founded by don Francisco de Viedma y Narváez on 22nd April 1779.
In February 1779 the pilot Basilio Villarino had been sent to explore the river Negro in the brigantine Nuestra Señora del Carmen, the first man who crossed that part of the river. Don Francisco de Viedma travelled up the river Negro in search of the most adequate settlement for the fort until 22nd April 1779. He found it at a distance of six or seven leagues from the outlet at about a hundred meters from the southern part, that is to say, in the spot where the building of the Centro Municipal de Cultura de Viedma is today.
Colonizing groups started arriving on 2nd October 1779 from León, Galicia, Asturias and La Maragatería, that is why those people born in Patagones are called maragatos. These families initiated a hard life, specially due to the enormous distance from all urban areas. Their resources were agriculture, cattle breeding, salt, grease, fish, flour, salted meat, sea lions, leather, and ham.
The first years in the fort comprised much sacrifice, and even when at the beginning the authorities looked interested in fostering development, soon everything turned into failed promises, isolation and poverty. The first colonists struggled for survival, but did not give up, and continued their work with a high spirit of decision.
In 1783, the Viceroy himself recommended the insurrection of the settlements in Patagonia, since they were onerous for the Crown. The fort was reduced to the category of military post, and the support was practically suspended.
In 1791 the new vicerroy Marqués de Loreto reconsidered the situation and gave a new impulse to the fort, but difficulties in communication and isolation conspired against them, and the situation aggravated to the point that their humble houses were gradually destroyed, and their inhabitants had to go and live in caves in the crags, for what they got their nickname.
For all this, the poorest colonist families of XVIII century in Fuerte del Carmen kept using these caves until the end of XIX century.
As we have seen, Carmen de Patagones is older than Viedma, and has been a corsair port, and battle scenery. At the beginning, Viedma was called Barrio Sud, then Mercedes de Patagones, until Colonel Alvaro Torres, governor of the Patagonian territory gave it the name of its founder.
These two cities were born together by the majestic river Negro on 13th June 1779, but the fort had to move due to a severe flood that lasted only half an hour, then the river went down again equally fast, leaving a vast desolation and forcing them to move the village to the left margin of the river.
On 19th June started the operation of tranferring everything to the north coast.
In 1826, the country started war with Brazil, and the port of Buenos Aires was blocked, for what the port of Patagones became the operation base for corsary ships that worked for the Argentine government. This situation gave an important impulse to Patagones, since economic activities based in agriculture and livestock, commerce with Buenos Aires and foreign countries increased, and soon conditions improved due to a rise in the labor demand, what gave to the area an important mobility and a promissory future.
The researcher and naturalist Alcides D´Orbigny travelled around Patagones in 1929 and in his report he tells us:
"...I finally arrived to a settlement situated to the north, over the plateau and its slopes. It shows an irregular group of small houses scattered around at different heights on the slope amid the sand, dominated by a fort in ruins, which could serve as a defence against the Indians. In the crags there were holes, excavations made by the first Spanish colonists to live in them, like others I saw along my way. To the south of the river I saw some miserable houses covered by haulms, and what I liked to see were some groups of tents from different friendly tribes, most of them Tehuelche, Patagon, or Puelche..."
Since the end of June 1899, the people from Viedma under the orders of engineer Schieroni, constructed a defence embankment in the slope called El Molino limiting the low parts of the clump of rushes. It was very difficult to contain the immense amount of water from the rush pond, which increased its volume very rapidly. They trusted that in the future the water would descend, but the news they received from the cordillera kept being alarming. Danger was confirmed: the water of the river raised its level on the coast of Viedma and Patagones.
On 16th July, the street called San Juan, today Sarmiento, was covered by the water. On 19th July, the embankment yielded and the water flooded over Viedma, but was contained by a second embankment built nearby. In the morning of 20th July, that second embankment was destroyed, and the water flooded over the Gobernación, and in less than an hour all public buildings were under a meter of water.
In 1878 Viedma achieved a privileged situation when the central government created the Gobernación de la Patagonia and appointed capital the city of Mercedes de Patagones, called Viedma in homage to its founder by decree of governor Don Alvaro Barros in 1879.
In October 1884, national territories were created by law, and the Gobernación de la Patagonia was divided into the National Territories of Neuquén, Río Negro, Chubut, Santa Cruz and Tierra del Fuego.
In 1914 the pier on the river Negro was inaugurated.
In the 30s the railroad bridge was inaugurated. It had previously been used as a dock for ships and rafts transporting goods that arrived at port Maragato from Patagones to Viedma.
On 22nd November 1922, the first train arrived to Carmen de Patagones hauled by the locomotive "La Maragata", today a historical monument.
The territory of Río Negro was declared province in 1955.