The Amazon River is widely recognized as the world’s largest river by discharge volume, moving a fifth of all the fresh water that flows into the world’s oceans. Its enormous drainage basin covers approximately 40% of the South American continent, making it a globally significant hydrological feature. This immense scale naturally raises questions about its depth, which is far greater than most river systems on Earth. Determining the absolute deepest point requires specific hydrographic measurements, as the river’s channel is constantly changing and its depth varies throughout the year.
The Maximum Measured Depth
The deepest part of the Amazon River is not a single, fixed point but is generally located in constricted sections of the lower river course. The maximum measured depth is typically cited around 100 meters (330 feet) in the central and lower Amazon basin. Localized measurements, however, have recorded even greater depths in certain narrow passages within Brazil.
One frequently referenced deep section is the Óbidos Narrows, near the city of Óbidos, situated about 600 miles from the Atlantic Ocean. This area is where the river’s immense width is dramatically constrained, forcing the water into a much deeper channel. Maximum soundings in this narrow stretch have reached 130 meters (about 430 feet).
An even greater measurement of 150 meters (nearly 490 feet) has been recorded further upstream near Itacoatiara. These extreme depths are not the average but represent specific, localized scour holes where the river’s powerful current has eroded the riverbed. The deepest points result from the massive water volume and local geology that forces the channel to narrow, creating a powerful jet effect that carves out the river bottom.
Geographic Factors Causing Depth Variation
The depth of the Amazon River is far from static, fluctuating dramatically in response to the region’s intense annual rain cycle. The water level can rise and fall by an average of 40 to 50 feet (12 to 15 meters) between the dry and wet seasons. This seasonal variation is caused by the massive scale of the river’s drainage basin, which receives rainfall across its vast expanse.
The rainy season, or cheia, typically peaks between November and June, causing the river to swell and flood the surrounding lowlands. During this time, the depth increases substantially, transforming the main channel and creating a huge, temporary freshwater ecosystem called the várzea. The immense size of the basin absorbs and releases water gradually, which prevents catastrophic flash floods.
The dry season, or vazante, sees the water levels recede, revealing vast sandbars and reducing the river’s width and depth. This natural pulsing is a defining characteristic of the Amazonian landscape. The immense storage capacity of the floodplain mitigates the effects of the seasonal rainfall, allowing for a predictable cycle of rising and falling water.
Contextualizing Scale: Depth Compared to Flow and Width
While the Amazon’s maximum depth of 330 to 490 feet is impressive, it does not hold the title for the world’s deepest river, a distinction belonging to the Congo River in Africa. The Amazon’s true magnitude is defined by its sheer volume and width, which dwarf other river systems globally. It discharges an average of over 200,000 cubic meters of water every second, a flow rate greater than the next seven largest independent rivers combined.
The river’s width during the low water season can range from two to six miles in many sections. During the height of the wet season, the river completely fills its floodplain, expanding to an astonishing width of 30 to 35 miles in some areas. This incredible lateral expansion, combined with the depth, accounts for the unparalleled discharge volume.
The depth is only one dimension of the Amazon’s overall scale, which is better described by its capacity to carry a massive, sustained flow across a huge geographic area. Its waters are so voluminous that the plume of freshwater can be detected hundreds of miles out into the Atlantic Ocean. This combination of depth, extreme width, and unrivaled discharge volume establishes the Amazon as the largest river system on Earth.