They probably sell more of them here than anywhere else. I’m sure they also make components all over the world, even if they do the final assembly here.
No, according to the Federal Trade Commission labeling requirements, at least 80% of the components have to be made in the US to have "Assembled in the USA" on the computer. No computer can say "made in the USA" or "Manufactured in the USA" because we don't even mine the raw materials to reach the percentages required to reach that standard and never can. They don't exist here.
The Mac Pros and iMacs both have "Assembled in the USA" etched on them and meet the FTC's standards. Therefore, they both have at least 80% American made components and the computers were substantially assembled in the USA. In the case of the Mac Pro, components are made in at least seventeen states, according to Apple, including Texas, Florida, Illinois, and Kentucky.