The Best -- and the Dirtiest -- Beaches in the U.S.

Just in time for the Fourth of July holiday weekend, the environmental watchdog group Natural Resources Defense Council released its 21st annual report card of 200 of the nation's cleanest and dirtiest beaches based on water quality.

While vacationers who booked beach places months in advance for this holiday weekend may not be able to change their plans, the report reveals which beaches could have issues with contaminated water, which may help keep beachgoers safe.

This year's report, "Testing the Waters: A Guide to Water Quality at Vacation Beaches," looked at the 2010 beach water testing results -- the most recent results available -- of more than 3,000 locations nationwide and gave star ratings to 200 beaches nationwide. Beaches in the Southeast, along the New York-New Jersey coast and in the Delaware, Maryland and Virginia regions had the cleanest beaches.