Marine Corps, which say a listing on the register will bring additional oversight that could interfere with the staging of military training exercises. The seven beaches – Uppers, Lowers, Middles, Church, The Point, Old Man's and Dog Patch – are part of San Onofre State Beach, which occupies a portion of the Camp Pendleton Marine base that the Navy leases to the state.

Orange County officials share the military's concerns and say Trestles is a no more significant a surf spot than Huntington Beach, Corona del Mar or Malibu. Some also worry that the historic designation would eliminate any possibility of someday extending the Foothill (241) Toll Road to the I-5. The Surfrider Foundation has been among the most vocal opponents of the extension.

On Tuesday, Orange County state Sens.Mimi Walters, R-Irvine, and Mark Wyland, R-Oceanside, put out a news release accusing former State Historic Preservation Officer M. Wayne Donaldson of "using state resources to manipulate the application of a federal historic designation" to further a personal campaign against the toll road extension. Donaldson, recently retired, testified in favor of the historic designation on Friday, saying, "This is a unique site in California, a unique start to the surf culture that went worldwide."

At the hearing, supporters also showed a video of Clint Eastwood reminiscing about Trestles and mentioned that they've received letters of support from two original members of the Beach Boys.

Speaking in opposition, Walters' aide Garth Eisenbeis cited a Dec. 20, 2012, news release on Surfline.com that referred to Friday's hearing and said, "The Surfrider Foundation