The Battle of Topter, or Battle of Calama, was fought on March 23, 1879 between Chile and Bolivia. It was the first battle of the War of the Pacific.

The Chileans were taking possession of the Antofagasta (Litoral) Province, then a part of Bolivia. The few Bolivian troops decided to make a stand in the town of Calama. On their way to occupy Calama, 554 Chilean troops, including cavalry and with two Krupp rifled guns, were opposed by 135 Bolivian soldiers and civilian residents led by Dr. Ladislao Cabrera, a civilian and a political authority in the region.

The Bolivians fought next to the Topter ford, which runs outside the city. Cabrera dug in at two destroyed bridges; calls to surrender were rejected before and during the battle. Outnumbered and low in ammunition, most of the Bolivian force eventually withdrew except for a small group of civilians, led by Colonel Eduardo Abaroa, that fought to the end.

The Bolivian national hero, Abaroa, died in the battle. Further ground battles would not take place until the war at sea had been completed.

The War of the Pacific (Spanish: Guerra del Pacífico), also known as the Saltpeter War (Spanish: Guerra del salitre) and by multiple other names, was a war between Chile and a Bolivian–Peruvian alliance from 1879 to 1884. Fought over Chilean claims on coastal Bolivian territory in the Atacama Desert, the war ended with a Chilean victory, which gained for the country a significant amount of resource-rich territory from Peru and Bolivia.

The war began over a nitrate taxation dispute between Bolivia and Chile, with Peru being drawn in due to its secret alliance with Bolivia. But historians have pointed to deeper origins of the war, such as the interest of Chile and Peru in the nitrate business, the long-standing rivalry between Chile and Peru, as well as political and economical disparities between Chile and Peru and Bolivia. On February 14, 1879, Chile's armed forces occupied the Bolivian port city of Antofagasta, subsequently war between Bolivia and Chile was declared on March 1, 1879, and between Chile and Peru on April 5, 1879.

Battles were fought in the Pacific Ocean, the Atacama Desert, the Peruvian deserts, and the mountainous interior of Peru. For the first five months, the war played out in a naval campaign, as Chile struggled to establish a marine resupply corridor for its forces in the world's driest desert. Afterwards, Chile's land campaign bested the Bolivian and Peruvian armies. Bolivia withdrew after the Battle of Tacna, on May 26, 1880. Chilean forces occupied Peru's capital Lima in January 1881. Remnants and irregulars of the Peruvian army waged a guerrilla war but could not prevent war-weary Peruvian factions from reaching a peace deal with Chile involving territorial cessions.

Chile and Peru signed the Treaty of Ancón on October 20, 1883. Bolivia signed a truce with Chile in 1884. Chile acquired the Peruvian territory of Tarapacá, the disputed Bolivian department of Litoral (turning Bolivia into a landlocked country), and the temporary control over the Peruvian provinces of Tacna and Arica. In 1904, Chile and Bolivia signed the Treaty of Peace and Friendship, which established definite boundaries. The 1929 Tacna–Arica compromise gave Arica to Chile and Tacna to Peru.