National marine sanctuaries are protected waters that include habitats such as rocky reefs, kelp forests, deep-sea canyons, and underwater archaeological sites

Within their protected waters, giant humpback whales breed and calve their young, temperate reefs flourish, and shipwrecks tell stories of our maritime history. Similar to national parks on the land, these underwater preserves provide a safe habitat for species close to extinction or protect historically significant shipwrecks.

Ranging in size from less than 2.6 square kilometers to 356,880 square kilometers (one square mile to 137,792 square miles), each sanctuary site is a unique place needing special protections. Marine sanctuaries are natural classrooms, cherished recreational spots, and valuable commercial industries.

Our national marine sanctuaries are part of a larger network called the National Marine Sanctuary System. The Sanctuary System consists of 14 marine protected areas that encompass more than 388,498 square kilometers (150,000 square miles) of marine and Great Lakes waters from Washington State to the Florida Keys, and from Lake Huron to American Samoa. The system includes 13 national marine sanctuaries and the Northwestern Hawaiian Islands Marine National Monument.

For more information:
Office of National Marine Sanctuaries
Diving Deeper Podcast, Episode 8 (May 6, 2009) - What is a national marine sanctuary?