After the War of the Triple Alliance, Brazil did succeed in preventing Argentina from getting territory to the north of the Pilcomayo: today that river constitutes the international boundary between the Argentine province of Formosa and the Paraguayan department of Presidente Hayes.
After the War of the Triple Alliance by a png-drawn out process Brazil did succeed in preventing Argentina from getting territory to the north of the Pilcomayo. Hence today that river constitutes the international boundary between the Argentine province of Formosa and the Paraguayan department of Presidente Hayes.