Lago Rosario is a village and municipality in Chubut Province in southern Argentina.

On April 30, 1902 the inhabitants of the Colony October 16, mostly Welsh, voted for which governments of Argentina and Chile to resolve a conflict of limits within the region.

In 1937 the Amaya brothers caused the eviction of the Aboriginal Reserve of Nahuelpan (G. Devera : 1999.

Report of Smoke, Trevelin : Municipal Directorate of Culture), about 30 km north of Lake Rosario, where more than 300 people were banished to in 1908.

Which resulted in several of these evicted families to migrate to Lake Rosario.