Quick shout out to the folks over at All American Clothing, a company established in 2002.
They offer Made in USA Certified garments.
They have items for men and women, and their selection includes shoes/boots, socks, belts, jeans, sweatshirts, coats, tops — and yes — t-shirts.
Tee Shirt / Undershirt Items
In checking through their tee shirt category, looks like they have some lightweight tees.
They come in white and also different colors, that could easily double as undershirts.
Short Sleeve V-Neck Tee Shirt (Style# vntee)
- Jersey 30/1 combed ring spun 100% cotton 4.4 oz
- White only
Ribbed Tank Top (Style# 9020)
- 2×1 Rib
- Looks like this item has been discontinued, but they still have some white tank top undershirts in stock
Crew Neck Tee (Style# AAT)
- 6.1 oz 100% Cotton
- Lots of color options
- Note: this is a little heavier, so if you don’t like thicker/heavier undershirts, this might not be for you
This is kinda cool too. On every pair of jeans (maybe on other items too), there is a traceability number where you can find out where the cotton on your jeans came from.
UPDATE: The traceability program was discontinued due to the closure of the cotton mill that provided the service.