The United States conquered and bought new lands over time, and grew from the original 13 colonies in the east to the current 50 states, of which 48 of them are joined together to make up the contiguous United States. These states, called the "lower 48", can all be reached by road without crossing a border into another country. They go from the Atlantic east to the Pacific in the west. There are two other states which are not joined to the lower 48 states. Alaska can be reached by passing through British Columbia and the Yukon, both of which are part of Canada. Hawaii is in the middle of the Pacific Ocean.