Muir Woods was designated the 10th National Monument for the United States of America. Although it was the 10th National Monument, it was the first in three very important ways. It was the first time a private individual (William and Elizabeth Kent) donated land to the federal government to create a National Monument. It was the first time a National Monument was created in an urban setting, just 12 miles north of San Francisco. And it was the first time the Antiquities Act of 1906 was used to preserve a living species, the Coast Redwood tree.