Iron Flask is made in the People’s Republic of China.
It is common for stainless steel water bottles. Even American brands like Hydro Flask, Takeya, Klean Kanteen, CONTIGO, and Cirkul are all China-made. Manufacturing this product in the US will double the production cost, making it impossible to market.
And no, they don’t bear the stereotypical low-quality misconception of “Made in China” items. No worries about its build.