All over the US. The best Amazon based display (Orinoco technically) I've ever seen is the Dallas World Aquarium. It's where I got my start. Another one of the largest is at the aquarium in Minnesota (now SeaLife MN). I created a 145,000 gallon Amazon there several years ago. They also have one of the largest (if not THE largest) FW displays out there - 220,000 gallons. It's displaying native North American fish.are they all roughly around your area? or different parts of the states?
if i'm ever nearby one i'd love to check it out