In a dataset of all U.S. colleges and universities, I decided to sort it based on a column for undergraduate enrollment. A single school popped up with only one enrolled student, the Institute for Advanced Medical Esthetics in Richmond, Virginia. No, I did not make up that name. Click on the link and see for yourself. This number makes no sense to me, and take it as a lesson in doubting data just as you'd scrutinize any source. Maybe there is only one student, but that seems unlikely. It is based on 2013 data and perhaps the school was just getting started.
(By the way, the largest listed, with 166,816 students, was no surprise -- University of Phoenix--Online campus. Next was Ivy Tech Community College in Indiana with 87,017 students. Wow).