Trenque Lauquen is a city in the west of the province of Buenos Aires, Argentina, 444 km (276 mi) from Buenos Aires City and 80 km (50 mi) from the border with the province of La Pampa, on the intersection of National Routes 5 and 33. Trenque Lauquen is the only city of the district (partido) of the same name, and has a population of about 40,000 inhabitants as per the 2001 census.
The name of the city means "Round Lagoon". It was founded on 12 April 1876 by the advancing troops of Colonel Conrado Excelso Villegas, under orders from the Minister of War Adolfo Alsina, as the center of operations of the North Division of the Border Commandancy, during the Conquest of the Desert (the campaign to subject the territories occupied by aboriginal tribes to the government of Buenos Aires). The partido was officially created on 1886-07-28.