Acadia National Park is one of the most intensively used national parks in the United States. While its annual visitation (2.2 million visits in 2004) does not rise to the levels of some of the “crown jewel” western national parks (Yellowstone National Park, for example, accommodated 2.9 million visits in 2004), visits to Acadia are concentrated on its comparatively small size of less than 50,000 acres. Yellowstone, by comparison, is spread across 2.2 million acres. Given the intensive character of visitor use at Acadia, it is vital to monitor recreational use and its associated impacts to help ensure protection of important park resources and the quality of the visitor experience.