Indirectly.... we stayed at a resort on Lake Wawasee in Syracuse, Indiana, and all their outdoor furniture was Polywood, which is made in the same town.
it was all several years old, exposed to northern Indiana weather and public use, and it all looked and functioned great, with no loose joints, etc. So although Polywood furniture seems very expensive, you do get what you pay for with that brand, and they really are made in the USA.
Just one small anecdotal data point. I have no idea whether the other brands or cheaper brands also hold up as well. And of course ordering any name brand through Amazon can have its pitfalls.