Shortly before 4 a.m., a large boulder and debris fell onto the highway near Dana Point Harbor Drive, officials said. Crews removed the large rock as well as mud and other rubble. The boulder was estimated to be about 10-by-20 feet.
A one-mile stretch of PCH was closed between Beach Road and Camino Capistrano.
Orange County sheriff's officials said the closure would last until around noon, but the highway was reopened earlier than expected.