Hot Springs National Park is a national park in the state of Arkansas. At a mere 5,540 acres, it is the smallest national park in the United States. It is so small, in fact, that the largest national park in the United States, Wrangell-St. Elias National Park, is 2,377 times bigger than it. The hot springs for which the park is named flow from the appropriately named Hot Springs Mountain. Hot Springs National Park is interesting because while Yellowstone National Park is considered the first national park, Hot Springs National Park was the first park in the National Park system (though wasn't considered a national park at the time). In fact, it is 40 years older than Yellowstone, first established in 1932. It became a national park on March 4, 1921.