The primary purpose of this context is to assist in the identification of places associated with the Underground Railroad that are eligible for National Historic Landmark designation and for listing in the National Register of Historic Places. In 1990, the United States Congress authorized the National Park Service to conduct a study of the resources available nationally for the interpretation of the Underground Railroad. A special resource study published in 1995 determined that there were sufficient resources available and suggested a variety of approaches for commemoration of the Underground Railroad. Operating under the 1990 legislation, the National Park Service has produced educational materials and technical support for researchers. An Underground Railroad Handbook was published in February 1997, followed by "Exploring a Common Past: Researching the Underground Railroad." This study provides historic context for the development of nominations for the Underground Railroad theme. Identifying historic properties associated with the Underground Railroad is an extremely varied task. To help the researcher understand the various aspects of the Underground Railroad, this context is divided into sections that focus on a complex but related series of historical activities and geographic regions, referred to generally as the Underground Railroad. The term is capitalized to signal inclusiveness in that larger organizing concept. When used as a descriptive adjective or as a reference to some part of the concept, it is not capitalized. This context is not exhaustive and it briefly reviews the history of slavery and of North American resistance to slavery, excluding Canada. It evaluates examples of structures, buildings, communities, regions and transportation routes related to fugitives from slavery. These examples do not encompass all the varieties of Underground Railroad activity that were ever enacted; no study could make that claim. However, this study provides a structure into which researchers may fit more information and evidence as it is developed. The report also describes aspects of antislavery activity and slave resistance which are precursors or marginal to the Underground Railroad story but which contribute to its emergence. This context study treats such events, often historically important in their own right, as connected but not central to the Underground Railroad story.