Looking at the merhandise for sale in Walmart, I think it safe to say the majority comes from outside of the US / Canada and mainly from China. Sure would help the trade deficit if the products were from "here".
However they likely would be more expensive, and the company wouldn't be where it is without being so much cheaper.
I look at all of the smaller cities that have a Wal-Mart on the edge of town, and then drive into that city and see all of the boarded up shops that couldn't compete. I for one would pay more for better quality products at the stores selling home made products.
The last place I would buy tools (other than flea markets) would be from Walmart. Cheap junk for the most part.