We are related to at least 20 Presidents though probably not close enough to get you invited to spend the night in the Lincoln Bedroom. For those who have long forgotten your American History lessons from High School or College, there are wikipedia links for each.
The charts show how we're related to the closest common ancestor. For some, there are many more relationhips than shown as the software will only show how the two principles descend from closest common ancestor.
They are also shown in the lists section.