It’s been called “America’s best idea”—and its relevance is more timely than ever. There are now 424 parks in the nationally maintained system—more than 85 million acres spanning coast to coast, across all 50 states, the District of Columbia and U.S. territories. In 2021, there were 297.1 million recreational visitors to American national parks, proving that these spaces are indeed for the people to appreciate and enjoy. From the oldest to the largest to the most fascinating—this is the story of our national treasures.