Entre Ríos (Spanish pronunciation: [ˈentɾe ˈri.os], "Between Rivers") is a central province of Argentina, located in the Mesopotamia region.

It borders the provinces of Buenos Aires (south), Corrientes (north) and Santa Fe (west), and Uruguay in the east.

The first inhabitants of the area that is now Entre Ríos were the Charrúa and Chaná who each occupied separate parts of the region.

As governor of Asunción first and then of Buenos Aires, Hernandarias conducted expeditions to Entre Ríos unexplored lands.

Juan de Garay, after founding Santa Fe, explored this area, which he called la otra banda ("the other bank").

However, the region remained entirely indigenous and uninhabited by Europeans until a group of colonists from neighbouring Santa Fe Province settled on the Bajada del Paraná in the late seventeenth century, now the site of the provincial capital.

Tomás de Rocamora further explored the area in 1783 under the threat of a Portuguese invasion from Brazil, and gave official status to many of the above-mentioned towns.

At this stage, European settlement was minimal, though during the May Revolution, the few colonists in the cities along the Paraná shore supported Manuel Belgrano and his army on his way to Paraguay.

On September 29, 1820, the leader (caudillo) Francisco Ramírez declared the territory an autonomous entity, the Republic of Entre Ríos.

In 1853, in a meeting of all the provinces except Buenos Aires, Paraná was elected as the capital of the Argentine Confederation, and the Governor of Entre Ríos and leader (caudillo) Urquiza as its first president.

At the time he was fulfilling his third term as governor of the province from 1860 to 1864 and after a voluntary interruption was reelected in 1886, but he was assassinated in 1870 after altogether 16 years of governing before finishing his mandate, which had probably been ordered by his supportor Ricardo López Jordán, not trusting him anymore.