Hello how may I help you? Where is the tallest indoor waterfall located? The tallest indoor waterfall is located at "Water You Looking At" theme park in Boise, Idaho, USA Where is the tallest waterfall (indoor or outdoor) located? I gave you the tallest indoor waterfall. Would you like the tallest outdoor waterfall? Yes. The tallest outdoor waterfall is at Lake Victoria Falls in Africa. How tall is it? 205 meters. Cool, thank you! You're welcome.