The Monitor National Marine Sanctuary is established as the first United States National Marine Sanctuary.

Monitor National Marine Sanctuary is the site of the wreck of the USS Monitor, one of the most famous shipwrecks in U.S. history. It was designated as the country's first national marine sanctuary on February 5, 1975, and is one of only two of the seventeen national marine sanctuaries created to protect a cultural resource rather than a natural resource. The sanctuary comprises a column of water 1 nautical mile in diameter extending from the ocean’s surface to the seabed around the wreck of the American Civil War ironclad warship, which lies 16 nautical miles south-southeast of Cape Hatteras, North Carolina. Average water depth in the sanctuary is 230 feet (70 m). Since it sank in 1862, Monitor has become an artificial reef attracting numerous fish species, including amberjack, black sea bass, oyster toadfish, and great barracuda.

A U.S. National Marine Sanctuary is a federally designated area within United States waters that protects areas of the marine environment with special conservation, recreational, ecological, historical, cultural, archeological, scientific, educational, or aesthetic qualities. The program was established in 1972 by the Marine Protection, Research, and Sanctuaries Act and is currently administered by the National Ocean Service through the National Marine Sanctuaries Act (NMSA).