The average depths of the Atlantic, with its adjacent seas, is 3,338 meters (10,932 ft); without them it is 3,926 metres (12,881 ft). The greatest depth, 8,605 metres (28,232 ft), is in the Puerto Rico Trench. The width of the Atlantic varies from 2,848 kilometers (1,770 mi) between Brazil and Liberia to about 4,830 kilometres (3,000 mi) between the United States and northern Africa. Source(s): http://en.wikipedia.org/wiki/Atlantic_Oc...