Jimmy Carter Jr.
Joining our list of the smartest US presidents is a Nobel Peace Prize winner – James Earl Carter, Jr. With an IQ of 156.8, his dreams of making the nation competent and compassionate were commendable, yet somewhat unrealistic at the time. He championed human rights and we salute him for doing so. However, his extreme intelligence could be a tad outlandish at times. He claimed to have seen UFOs after a 1976 conference in Georgia.