The US has two main Caribbean Regions: Puerto Rico and the US Virgin Islands. These two different groups are located near each other. The US Virgin Islands are part of the Anegada Passage where the shipping for the Panama Canal passes. The islands that are part of Puerto Rico are located in the Mona Passage shipping lane of the Panama Canal. Both groups of islands are located in the Caribbean Sea. The islands of Puerto Rico and Virgin Islands were at one time a part of the Spanish West Indies.