Interesting that it dethroned last years car, the Jeep Wrangler. This was due to the JL having many more foreign sourced parts:
https://www.cnet.com/google-amp/news/cars-com-american-made-index-2018-jeep-cherokee/
https://www.cnet.com/google-amp/news/cars-com-american-made-index-2018-jeep-cherokee/