From mask mandates, to testing requirements to vaccine availability to (sometimes) no requirements at all, the various rules and regulations not only differ by state, but sometime even by major cities with the states.
Below is a complete set of links for the latest authoritative (and regularly updated) in all fifty states and Washington DC (in alpghabetical order).
Updated April 2, 2021: The CDC has announced that Americans who are fully vaccinated against COVID-19 can resume travel at low risk to themselves. Read the new guidelines here.
Congratulations, you're on your way to that next dream vacation.
Keep an eye out for the Deal of the Week and other offers that will help get you there fast.