The wagon trail between Salt Lake City and Los Angeles is one of the most important but least-known roads of nineteenth-century western migration. Known as the Southern Route, it included the western half of the Old Spanish Trail and was favored because it could be used year-round. This book is the first history of the complete Southern Route and of the people who developed and used it. Based on extensive research in primary sources, including many early travelers' accounts, and on the author's own traverse of the route and its branches, the book discusses the exploration and development of the Old Spanish Trail. In addition, Lyman's discussions of Mormon-Indian relations and of the infamous Mountain Meadows Massacre offer fresh and important analyses of these vital aspects of the westward movement.