Evaluating the largest fanbases in college basketball involves analyzing television ratings, merchandise sales, arena capacities, and social media engagement across the United States. Iconic programs with rich historical traditions, multiple national championships, and massive national followings—such as the Kentucky Wildcats, North Carolina Tar Heels, Duke Blue Devils, Kansas Jayhawks, and Indiana Hoosiers—consistently command the largest and most passionate fanbases in the sport. These programs draw millions of devoted supporters who travel across the country to fill arenas, dominate television viewership metrics, and maintain vibrant communities of alumni and casual fans alike, making their collective presence a dominant force throughout the entire collegiate basketball landscape.