Primero de Marzo (or 1° de Marzo) is a small town and district in the marshy lowlands of the Cordillera Department in Paraguay. The area is located near the shallow meandering river Yhaguy which locals utilize primarily for fishing and recreation. Primero de Marzo's name is derived from the date March 1, 1870, when then Paraguayan President Francisco Solano López was killed by Brazilian troops at Cerro Corá, thereby ending the bloody War of the Triple Alliance.