100 years ago today, on August 25, 1916, the National Park Service was created by an act of Congress, signed by President Woodrow Wilson. The act was originally codified in Title 16 (Conservation) of the United States Code. In 2014, it was recodified in Title 54 (National Park Service and Related Programs).
Check out the exhibit at Thomas Cooper Library celebrating 100 years of national parks. The exhibit is in the Government Documents and Maps section, Level 5, through September 30.