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.

The presence of water, mainly rivers, contributed to the locations of early pioneer settlements in the Nebraska Territory from 1855 to 1866. In Pioneer Settlement of Nebraska Territory, author Charles Howard Richardson presents the findings from a study conducted about factors that influenced Nebraska's early development. Pioneer Settlement of Nebraska Territory explores the classification, distribution, and characteristics of both the populated and rural areas during this ten-year time period. With charts and illustrations included, Richardson describes how the settlers at major Missouri River towns depended on outfitting westbound emigrants for their livelihood. He also describes how the outlying territory, generally unoccupied, was confined to the lower reaches of tributary streams, where surface water was available throughout the year. Focusing on the eastern third of the territory, roughly 24,000 square miles, Richardson shows that early imports and exports were shipped by means of Missouri River boats between St. Louis and Omaha, and that the East-to-West transportation links consisted mainly of overland wagon roads because there were no navigable rivers in this pre-railroad period. Pioneer Settlement of Nebraska Territory provides insight into Nebraska's earliest development.