The New Student's Reference Work/Madeira (river)
Madei'ra, a river of South America and the largest tributary of the Amazon, is formed by the junction of the Mamoré and Guaporè in Bolivia, the Beni joining about 100 miles lower down. The river then flows northeast, its drainage-basin embracing nearly 500,000 square miles. From its mouth to its first falls the distance is nearly 600 miles; and above this point navigation is rendered impossible by a series of falls and cataracts extending over 200 miles. The length of the river, including its tributaries, is about 2,000 miles. See Bolivia.