With over 15 million visitors in 2014, Golden Gate National Recreation Area
is the most popular NPS unit in the whole of America, not just in the West. The park was created in 1972, and contains a great variety of sites in and around San Francisco, ranging from the undeveloped hills and valleys of the Marin Headlands, to forts and other military artifacts within the city limits. The preserve includes 59 miles of the Pacific coast, and Alcatraz Island. The famous Golden Gate Bridge is not part of the NRA, though many of the best viewpoints are. Most sites are free to enter.
: 15,004,420Golden Gate National Recreation Area - full description