There are parts of the Leatherman line made everywhere; the plier heads, in particular, are cast in Mexico; the company Leatherman contracted to make them moved their production south, and instead of finding someone else to cast them, they kept with the same company for a number of reasons. So far as I know, though, yes, it is assembled in the US.
[Edit: I'm not implying that because they're made with parts elsewhere, that they're inferior products. They're one of the big four, you can't go wrong with them.
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