Finding a "US made" portable jump starter is probably impossible. Most, if not all, of the SLA batteries inside will not be made here.
I used to have a "Vector" portable jump starter that lasted a good 8+ years of hard service. After that died, I just bought a standard marine starting battery. They come with bolts for wire lugs and a nylon strap to carry it, and have high cranking amps. It was only $49 too. I made my own set of jumper cables that simply bolt onto the battery with some normal wire lugs. (cut the aligator clips off one end of a normal set of jumper cables)