1986 Map of Lisbon Gap

About this map

Island Mesa and Middle Mesa define the high ground of this high-desert landscape along the Utah-Colorado border, where the terrain breaks sharply into the Lower Lisbon Valley. This mid-1980s survey captures a geography defined by its drainage systems and mineral exploration, with several prospects and a mine located east of the state line. The namesake Lisbon Gap serves as a critical passage through the uplift, while named drainages like Snyder Water Canyon and Greasewood Canyon illustrate the erosional patterns of the Colorado Plateau. The map also records the jurisdictional intersection of San Juan County, Utah, with Montrose and San Miguel Counties in Colorado. For those tracing the history of resource extraction, the presence of various drill holes and survey points near Horsethief Point provides a record of late-20th-century industrial activity in this sparsely settled region.