There are four groups of eagles: Sea or Fish Eagles, Booted or True eagles, Snake or Serpent eagles and, Harpy or Buteonine Eagles. Eagles are placed in the buteos genus (like hawks) but have longer wings.
The four eagles found in North America are the Bald Eagle, the Golden Eagle, the Steller's Sea Eagle and the While-Tailed Eagle. The Bald Eagle (a Fish Eagle) and the Golden Eagle (a Booted Eagle) are the most common.
A common mistake is made when trying to distinguish between an immature Bald Eagle and a Golden Eagle. A Bald Eagle does not get its white head and tail until it's about 4 or 5 years old, but one way the two can be distinguished is by the feathering on their legs. A Golden Eagle has feathers clear to where its toes begin, while a Bald Eagle has bald legs with yellow scales from about halfway down.