I too try to buy American whenever possible. I feel that it's been getting easier in the last few years, particularly with clothing. Here are some companies that I like to purchase everyday clothing from. Unfortunately most of the stuff has to be purchased online and tried on at home and exchanged. Its frustrating but worth it. I've actually had good luck sourcing USA made clothing on eBay. Sometimes you can find new old stock.
www.danner.com - I hesitate to recommend footwear, as everyone's sizes vary. I typically don't like Danner, as they just don't fit me, but recently I bought a pair of their "Mountain Pass" boots, which are a lighter weight but still capable boot. They must have used a wider last, because they are the first Danners that are comfortable (for me).
www.sweatshirtsusa.com - "Kellsport" hooded sweatshirts- super heavy duty 18oz cotton, great construction, generous fit. I've got one of their hoodies, and a pair of their sweatpants on order. A good cotton hoody is a nice thing to have.
www.royalapparel.com for t-shirts
https://dearborndenim.us/ for jeans
www.atlas46.com for jeans
https://darntough.com/ for socks
www.thunderboltsportswear.com - Local (to me) maker of no frills Schoeller softshell pants/shorts with jeans styling. No fancy/unnecessary features. Just pants with pockets and belt loops. Truly can be worn outdoors on the trail, or as everyday pants. I haven't had them for too long, so I can't comment on them from a long term perspective, however I have had pants with the same fabric, and it's great durable stuff.