Continental U.S. means all the U.S. territories within the continent of North America, including Alaska and Hawaii. Mainland U.S. means all the states within the main land area. This would exclude anything off of the coast, such as Alaska and Hawaii, since they are outside the mainland borders.

I presume Mainland US excludes Alaska and Hawaii. It certainly excludes Hawaii. I have never heard the term Mainland US before. The US has only one government. There is an American Samoa, though. Anyone know about the government there?

It would be fun to live in Hawaii!

The American coastal shelf is a large continental shelf that extends from the mainland of North and South America