HAMPTON BEACH — In the center of the pristine New Hampshire coastline is a crown jewel of beaches, recognized nationally as one of the cleanest in the country.

On Wednesday, the Natural Resources Defense Council released its 21st annual beach water quality report in which Hampton Beach State Park achieved “Superstar Beach” status.

The report provides a five-star rating guide of 200 of the nation’s most popular beaches, evaluating them for water quality and best practices for testing and public notification. This year, for the first time, NRDC awarded “Superstar Beach” status to four United States beaches featured in their guide. These beaches, including Hampton, received special notice for having perfect testing results for the past three years, indicating a history of very good water quality.

Sonya Carlson, beach inspection program coordinator with the New Hampshire Department of Environmental Services, said a high bacteria advisory has never been posted at Hampton Beach since they started posting advisories in 2002.

“It just makes yet another reason why we continue to say to people that it’s time to come to Hampton Beach, which is the true jewel of the State of New Hampshire and its state parks,” said John Nyhan, chairman of the Hampton Beach Area Commission.

He said the cleanliness of the beach is not just about water quality, but about the state parks staff and local volunteers who keep the beach clean.

“I think it is a message that is being sent out to the world of tourism that Hampton Beach is a beautiful beach area, probably the prettiest in the Northeast, and also continues each year, with the hard work of everyone involved, to be the cleanest beach, and I think a lot of that has to do not just with water quality but with how we keep the beaches very clean,” Nyhan said.

New Hampshire as a whole also fared well in the report, earning first place for beach water quality with the lowest rates of contamination in the nation last year, at just 1 percent.

Wallis Sands Beach at Wallis Road also received a five-star rating, and Wallis Sands State Park received four stars.

The NRDC’s report analyzed government data on beach water testing results from 2010 at more than 3,000 beach testing locations nationwide.

Under the federal BEACH Act, states regularly test their beach water for bacteria found in human and animal waste. Sixteen New Hampshire beaches are tested regularly, many of them, including Hampton Beach, multiple times each week.

The full report, including a summary on the New Hampshire data, is available at www.nrdc.org/beaches.