The high school with the largest basketball gymnasium in the world is New Castle High School, located in New Castle, Indiana. The legendary New Castle Fieldhouse boasts a staggering seating capacity of over 8,400 to 9,300 spectators, accommodating more fans than the home arenas of many major NCAA Division I collegiate basketball teams. This massive architectural marvel stands as a permanent tribute to the profound cultural phenomenon of high school basketball passion and regional sports heritage across the state of Indiana.