The map, created by David M. Barreda, the Director of Visuals for China File, uses the information from Apple, Inc. "Suppliers List 2013." The list gives details on the major manufacturing locations of the suppliers of raw material and components, and the facilities that do final production for Apple products.
China File writes, "Neither China watchers nor Apple watchers will be particularly surprised to note that the vast majority of Apple suppliers happen to be in Asia. In fact, out of the 748 listed, more than 600 are in Asia. Of these, 331 suppliers are in mainland China."
You can click through to use the interactive map. From there you can zoom in to locations around the world -- and find out just how much is actually done in the US. As we know, Apple has been moving to have more of its products manufactured here in the states, and the number of and locations of suppliers and manufacturers is interesting to see.
Interestingly, no suppliers are noted in Africa, where the Democratic Republic of Congo is a supplier of some minerals used in electronics. This is a highly controversial topic, as minerals coming from the area are considered "conflict minerals" or minerals mined and sold to fuel war. While Apple has said it requires its suppliers to use conflict-free minerals, Steve Jobs himself said that it is impossible to know for sure where the minerals actually come from. So there is a possibility the list isn't exactly as thorough as one might wish -- even as thorough as Apple might wish it to be.