Hello!

The best resource on origins and destinations of the slave trade is the Trans-Atlantic Slave Trade Database, available online here. Here is a permalink showing the regions of Africa where slaves were loaded onto ships, and which areas in North America they arrived in. You can edit the table to show you mortality, change in areas over time, change in carriers, etc. Overall the database has records of 1,764 slave ships that disembarked slaves in North America. Also check the estimates tab which shows the approximate number of slaves disembarked directly from Africa (c. 400,000), and with the addition of slaves imported from the Caribbean (c. 100,000 per O'Malley, "Beyond the Middle Passage" WMQ 2009), brings a total of about 500,000 slaves in North America.

Senegambia - 56,530

Sierra Leone - 31,183

Windward Coast - 16,784

Gold Coast - 31,428

Bight of Benin - 8,324

Bight of Biafra - 50,122

West Central Africa and St. Helena - 73,143

Southeast Africa and Indian Ocean islands - 5,543

Other Africa - 94,302

Totals - 367,359

Places like the Gold Coast are underrepresented because they contributed a large portion of the slaves shipped to the British Caribbean, which transshipped slaves to North America.