"National Parks of the United States" examines why visitation will always vary among the national parks just as it did at the time this is covered by this study, the early 1950s. It explores the factors that attract visitors to the National Parks and those that have no bearing on the action of visitors. There is a rank correlation method that reveals the relative degree of attraction among factors that are responsible for the number of visitors flocking to each of the national parks. Because the central problem examined by this study is that of accounting for variations in the numbers of visitors to the various national parks of the United States, the analysis employs some widely accepted hypotheses concerning national park visitation. By reviewing such factors as nearly fishing streams, the availability of campsites, and the populations of towns near each park, this study paints a picture of what attracts visitors to one park over another. The natural beauty of each of these parks also provides the backdrop for the facilities that are made available and thus have a tremendous impact upon visitor attendance and activities such as hiking, camping, fishing, and climbing.