The Amazon River flows into the Atlantic Ocean. Before the Andes Mountains were lifted up during the geological Laramide Revolution about 65 million years ago, the Amazon flowed into the Pacific Ocean.
Where it meets the Atlantic, the mouth of the Amazon is over 250 miles wide. Water from the Amazon discharges into the Atlantic at approximately 5.5 million cubic feet per second, which is about 1/6 of all fresh water discharging into oceans around the world.
At about 4,075 miles in length, the Amazon River is the second-longest river in the world, just slightly shorter than the Nile. The Amazon begins high in the Andes and collects water from more than 1,100 major tributaries.