Posadas, city, capital of Misiones provincia (province), northeastern Argentina. Situated in the western corner of the province, it is bordered (north and east) by the Paraná River, which separates it from Encarnación, Paraguay.
The settlement originated as a Paraguayan trading post and river port, known as Trinchera de los Paraguayos (“Trench of the Paraguayans”). In 1869, during the War of the Triple Alliance, however, the name was changed to Trinchera de San José. In 1879 the city was named for the national hero, Gervasio Antonio Posadas (1757–1833). An administrative centre, with a substantial portion of its population working in public service, Posadas is also important for the manufacture of wood and iron products. Pop. (2001) 252,981; (2010) 324,756.