Gualeguaychú is a city in the province of Entre Ríos, Argentina, on the left bank of the Gualeguaychú River. It is located on the south-east of the province, approximately 230 km north-west of Buenos Aires. It has a population of 109,266 according to the 2010 Census.

Fray Bentos is the capital city of the Río Negro Department, in south-western Uruguay, at the Argentina-Uruguay border, near the Argentine city of Gualeguaychú. Its port on the Uruguay River is one of the nation's most important harbours. The city hosts the first campus of the Technological University, beside the historically relevant industrial complex Anglo, a World Heritage Site.