Most cruises in the U.S. go to islands in the Caribbean Sea, or other islands like the Bahamas which are technically in the Atlantic. 
Cruises to the Caribbean usually go to either the Western Caribbean, Eastern Caribbean, or Southern Caribbean.
To see map of where cruises depart from in the U.S., and go to in the Caribbean, click here! 
There are also cruises departing from California which go to Mexican ports like Cabo San Lucas and Mazatlan. 
Cruises from Seattle and Vancouver go to Alaska. 
There are a few 15-day cruises which go from the West Coast of the U.S. to Hawaii, but most Hawaiian cruises begin and end in Hawaii. 
There are many cruises departing from southern Europe which cruise to other ports in the Mediterranean Sea, usually either on the Western side of Italy toward Spain, or on the Eastern side toward the Greek Isles. 
Cruises depart from Northern Europe cruise the North Sea to the Norwegian Fjords and cities in the Baltics and Russia. 
Cruises go everywhere in the world, including all over Asia, Africa, the Middle East, Australia and New Zealand. 
There are also TransAtlantic and Repositioning cruises which cross the Atlantic or Pacific Ocean.