People often imagine that Theodore Roosevelt started the National Park system, but it actually began much sooner. On this date in 1872, President Ulysses S. Grant signed the Yellowstone National Park Protection Act into law. However, Roosevelt did create five national parks doubling the number, and he’s known as the “Conservation President.” He protected over 230 million acres of public land, setting aside 150 national forests, the five national parks, America’s first 18 national monuments, the