The 48 American states whose borders are shared with one or more states are contiguous. The remaining two states, Hawaii and Alaska, do not have borders that touch any other American state. They are, therefore, not contiguous states.
The "contiguous" states are the ones that are directly connected to the other states, often referred to as the "lower 48". The only TWO states that are not contiguous are Alaska (north and west of Canada) and Hawaii (an island chain in the tropical Pacific Ocean).
A state outside the contiguous US is the area that stretches from the west coast to the east coast and from the Canadian border to the Mexican border. Two states are outside the area, Alaska and Hawaii.