Robert Moses considered it his crown jewel.

Now two preservation groups want to ensure that Jones Beach State Park is preserved as the storied architect envisioned it — a miles-long public oceanfront with the amenities of a private resort. To that end, the Preservation League of New York yesterday named Jones Beach to its list of “Seven to Save” most threatened historic resources, hoping to call attention to its historic and cultural importance.

“It’s a model for all state parks,” Alexandra Wolfe of the Society for the Preservation of Long Island Antiquities said. The society sought to get the park on the list. Built in 1929, Jones Beach draws some 6 million people annually to its 6.5 miles of ocean beach and two-mile boardwalk on the south shore of Long Island.

Just 33 miles from Manhattan, the park offers landscaped gardens, swimming pools, basketball courts, paddle tennis, shuffleboard, miniature golf, softball fields, volleyball courts, bathhouses, and boat basins.

An 8,000-seat amphitheater attracts thousands more with an eclectic mix of concerts ranging from the Allman Brothers Band and Aerosmith to Josh Groban and Britney Spears.

Many original details — from intricately carved wooden bathhouses to a colorful cement mosaic and a 231-foot-tall brick-and-stone water tower modeled after the Campanile in Venice — have been preserved but are in need of repair or restoration, a league official, Erin Tobin, said.

“It needs extra attention and care, and that’s why we’re saying that it’s threatened,” Mr. Tobin said. “If we don’t pay attention to this now, it could be lost.”

The two groups are not opposed to commercial development coming to Jones Beach but object to the “scope and scale” of a plan submitted by Donald Trump for a $40 million catering facility on the state-leased land.

They also object to a one-acre parking lot he wants to build on the south side of the beach. Ms. Wolfe said the parking lot would go against Moses’s plan to relegate all parking to the park’s north side.

A message left with the Trump Organization was not immediately returned.

The two preservation organizations want the state parks department to create a master plan for the overall preservation of the park. Repairs and restoration are currently done on a piecemeal basis.

Governor Spitzer, in his State of the State address last week, earmarked $100 million for state parks, money that will allow the state parks department “to do the kind of work that is necessary at Jones Beach, to restore it to its grand status,” a parks department spokeswoman, Eileen Larrabee, said. Fewer than 10% of state parks have active and usable master plans, she said, and the new commissioner, Carol Ash, “has identified master plans as one of her priorities.”