I know of:
The only US maker I know of that civies can get (if you pay $200 or more) is by Camo Distributing, which is in Alabama. I haven't purchased any of their uniforms since I don't have a need for $200 worth of BDUs, and couldn't find anyone to do a group buy with. I also like my shirts to be configured with pockets on the sleeves, and they don't do this, unless you buy a LOT of them.
The following are made overseas, but sometimes with US materials:
1. Propper (most of mine say Made in Honduras or Dominican Republic of US materials)
2. Tru-Spec/Atlantco (Made in Korea)
3. Rothco (Chicom made)
4. Frank Bee (claims to be a US DoD contractor, but shipped me Rothcos and charged me for the US made prices) When I called them on it, they said they didn't have US made tan and OD BDUs in XL Long sizes. They may actually have a good US made product, but I never saw it. I got my money back.