The Chaco War ends as a ceasefire is negotiated between Bolivia and Paraguay.

Chaco War, the costly conflict between Bolivia and Paraguay. Hostile incidents began as early as 1928 over the Chaco Boreal, a wilderness region of about 100,000 square miles north of the Pilcomayo River and west of the Paraguay River that forms part of the Gran Chaco. The conflict stemmed from the outcome of the War of the Pacific, in which Chile defeated Bolivia and annexed that country’s entire coastal region. Thereafter, Bolivia attempted to break out of its landlocked situation through the Río de La Plata system to the Atlantic coast; athwart that route lay the Gran Chaco, which the Bolivians thought had large oil reserves.

Bolivia seemed to enjoy overwhelming advantages over Paraguay: it had thrice the latter’s population, an army well-trained by the German general Hans von Kundt, and an ample supply of arms purchased by loans from American banks. But the morale of Bolivia’s army of Indian conscripts was low, and Paraguayans were better fitted to fight in the lowland swamps and jungles, in which many Bolivians died of disease and snakebite as well as gunfire. Both countries had maintained military posts in the disputed region.

In April 2009 Bolivian President Evo Morales and Paraguayan President Fernando Lugo signed an accord resolving the countries’ border dispute over the Chaco region that had resulted in the war. The leaders agreed that the war had been brought on by foreign interests.