The word "borderlands" has many meanings in North American historiography, but this short overview focuses on the time and place that American historians have long known as the "Spanish Borderlands." Historian Herbert Eugene Bolton, the much-studied father of what came to be known as the "Bolton School," popularized the term "Spanish Borderlands" in a book of the same title, published by Yale in 1921. Bolton defined the Spanish Borderlands as those parts of the United States once claimed by Spain, from California to Florida, thus situating the Borderlands within the framework of United States history. This author's own survey of the field, "The Spanish Frontier in North America," published in 1992, followed Bolton's anachronistic model of placing a frontier of an empire within the boundaries of a nation that did not then exist. His borderlands, like Bolton's, included the region from California to Florida, but in this paper he restricts himself to discussing the western borderlands, from California to Texas, and some of its recent Anglophone historiography. Twenty years ago, the author concluded an examination of the historiography of the Spanish Borderlands by suggesting that its historians should stop "walking uneasily on the narrow edges of empires...[and] recognize that they have a secure foothold in both English- and Spanish-speaking America. As the juncture of those two worlds continues to grow in population and in economic and strategic importance, the perspective of Borderlands historians seems likely to become increasingly valued." Today, looking back over the last two decades, it appears to him that it has. (Contains 51 notes.)