Santa Rosa Creek Preserve is an area that includes valuable riparian forests and coastal wetlands, which provide habitat for endangered tidewater goby.

San Simeon Natural Preserve consists of vast wetlands, riparian zones, and several undisturbed native plant communities, including unique mima mound topography.

In 2005 an additional 1,100 acres (445 ha) of coastal lands were added to the state park following an easement agreement and property exchange with the neighboring Hearst Ranch.

The site has been dated to 5850 years before the present, and it contains significant evidence documenting prehistoric technology, subsistence practices and social organization over the course of several centuries.

A large elephant seal rookery is found on many beaches of Hearst San Simeon State Park.