D1 basketball refers to Division 1 basketball, which is the highest level of college sports competition in the United States. Division 1 basketball colleges are comprised of the most elite basketball programs in the country, and there are currently more than 350 Division 1 basketball colleges in the nation. To be a D1 athlete, you must participate in a college sports program that is a member of the NCAA Division 1. Getting to the D1 level and staying there requires an extremely high level of dedication, passion for the sport, and hard work. D1 basketball is the most competitive level of basketball, and there are different levels of D1 basketball, including low major, mid major, and high major or Power 5.