Already in USA with H1B, want to visit Puerto Rico

[trb88]

I have H1B status, but not a valid visa stamp in my passport. I'm already in the USA, want to go to Puerto Rico, and then come back straight to USA. Do I need a visa? Will I need a passport?
For my native country, Puerto Rico does require a visa, but given that I'm in USA, I don't know if I really need it.

[rayb]

Travelling to and from Puerto Rico and the U.S is the same as travelling between California and Nevada. But when boarding a plane in San Juan to return to the U.S. extra scrutiny is given to your documents because of the high rate or illegal entrants coming through PR from other Caribbean countries (Haiti, Dominican Rep, etc.). Puerto Rico, although not a state or territory, has "commonwealth" status with the U.S. and free movement of travelers.

--Ray B

I have H1B status, but not a valid visa stamp in my passport. I'm already in the USA, want to go to Puerto Rico, and then come back straight to USA. Do I need a visa? Will I need a passport?
For my native country, Puerto Rico does require a visa, but given that I'm in USA, I don't know if I really need it.