History of the Amazon River Timeline

Early scientific, zoological, and botanical exploration of the Amazon River and basin took place from the 18th century through the first half of the 19th century.

Charles Marie de La Condamine explored the river in 1743, contributing important scientific observations about the Amazon.

Image source: Charles Marie de La Condamine

This situation changed dramatically during the 20th century, with expanded development and transformation of the Amazon basin.

More than 5,600 species were known as of 2011, and approximately fifty new species are discovered each year. The candirú, a parasitic freshwater catfish, is just one of more than 1,200 species of catfish in the Amazon basin.

Paralleling the Amazon River is a large aquifer dubbed the Hamza River, flowing far underground. The discovery was made public in August 2011.

Image source: Hamza River

Contos continued downstream to the ocean and finished the first complete descent of the Amazon from its newly identified source in November 2012, a journey later repeated by two groups after the news spread.

Image source: Source of the Amazon River

In recent years, the Amazon River has experienced historically low water levels, the lowest in over a century, threatening ecosystems and river communities.

Image source: 2023–2024 South American drought

In 2022, the region's severe drought led to a devastating increase in water temperatures, reaching 39.1 degrees Celsius, causing the demise of 125 Amazon river dolphins.

Image source: Amazon river dolphin

For most of the 18th–19th centuries and into the 20th century, the Marañón was generally considered the source of the Amazon.

Image source: Marañón River

Fritz proposed that the Marañón River must be the source of the Amazon, noting on his 1707 map that the Marañón has its source on the southern shore of Lake Lauricocha, near Huánuco. He reasoned it was the largest branch encountered upstream and lay farther west than any other tributary.

Studies published in 1996, 2001, 2007, and 2008 identified the snowcapped 5,597 m Nevado Mismi peak, roughly 160 km west of Lake Titicaca, as the most distant source of the river. The headwaters of the Apurímac River had been considered the basin's most distant source for nearly a century.

Image source: Mismi

In June 2007, Guido Gelli, director of science at the Brazilian Institute of Geography and Statistics, told London's Telegraph newspaper that the Amazon could be considered the longest river in the world.

In July 2008, the Brazilian Institute for Space Research published a news article claiming that the Amazon River was 140 km longer than the Nile.

In 2009, a peer-reviewed article concluded that the Nile is longer than the Amazon, stating a length of 7,088 km for the Nile and 6,575 km for the Amazon, measured using satellite image analysis and field investigations to the source regions.

A 2014 study by Americans James Contos and Nicolas Tripcevich in Area, a peer-reviewed journal of the Royal Geographical Society, identified the most distant source of the Amazon as actually being in the Río Mantaro drainage on the Cordillera Rumi Cruz in Peru, ending nearly a century of consensus around Nevado Mismi.

Image source: Mantaro River

The Cabanagem revolt (1835–1840) was directed against the white ruling class in the Amazon region of Brazil.

Image source: Cabanagem

The population of the Brazilian portion of the Amazon basin in 1850 was perhaps 300,000, of whom about 175,000 were Europeans and 25,000 were slaves.

Image source: Amazon basin

On 6 September 1850, Emperor Pedro II of Brazil sanctioned a law authorizing steam navigation on the Amazon and gave the Viscount of Mauá the task of putting it into effect.

Image source: Irineu Evangelista de Sousa, Viscount of Mauá

The Viscount of Mauá organised the Companhia de Navegação e Comércio do Amazonas in Rio de Janeiro in 1852; in the following year it commenced operations with four small steamers: the Monarca, the Cametá, the Marajó, and the Rio Negro.

At first, navigation was principally confined to the main river; even in 1857 a modification of the government contract only obliged the company to a monthly service between Pará and Manaus, a second line making six round voyages a year between Manaus and Tabatinga, and a third making two trips a month between Pará and Cametá.

In the 1860s, approximately 3,000 tons of rubber were being exported annually; by 1911 annual exports had grown to 44,000 tons, representing 9.3% of Peru's exports. Iquitos grew from 200 people in 1851 to 20,000 by 1900.

Image source: Amazon rubber cycle

On 31 July 1867, the Brazilian government decreed the opening of the Amazon to all countries, limited to certain defined points: Tabatinga on the Amazon, Cametá on the Tocantins, Santarém on the Tapajós, Borba on the Madeira, and Manaus on the Rio Negro.

The Brazilian decree opening the Amazon to international navigation took effect on 7 September 1867.

The first direct foreign trade with Manaus commenced around 1874, boosting the city's role in the rubber economy.

Four centuries after the European discovery of the Amazon river, the total cultivated area in its basin was probably less than 65 km², excluding limited and crudely cultivated areas among the mountains at its extreme headwaters.

By the turn of the 20th century, the exports of the Amazon basin were India-rubber, cacao beans, Brazil nuts, and minor products such as pelts, resins, barks, woven hammocks, bird feathers, live animals, lumber, and gold.

With a population of 1.9 million people in 2014, Manaus is the largest city on the Amazon.

Image source: Manaus