From the mid-eighteenth century to the late-nineteenth century, Apachería, a region of shifting contours spanning what is today west Texas, Arizona, and New Mexico in the United States and Coahuila, Chihuahua, and Sonora in Mexico, was marked by a remarkable and persistent tendency toward political autonomy on the part of both its mestizo and Indigenous residents. This historical phenomenon and the attempts of the Spanish colonial and Mexican governments (at times in conjunction with their U.S. counterparts) to establish comprehensive state control in the region are the subject of The Wayward Edge.