2020 Map of Big Costilla Peak

About this map

Big Costilla Peak dominates this high-altitude landscape along the border of New Mexico and Colorado, where the headwaters of the Sangre de Cristo Mountains form a complex drainage system. The terrain is defined by the Costilla Reservoir in the southeast and a network of glacial features, including the Glacier Lakes and uniquely named alpine basins like Lake Number One and Lake Number Two. Multiple tributaries, such as Costilla Cr, Casias Cr, and Sanhistevan Cr, carve through the steep relief, reflecting a watershed that has historically supported ranching and irrigation in the lower valleys. This map illustrates the intersection of Taos County, New Mexico, and Costilla County, Colorado, at State Line Peak, documenting a remote section of the southern Rockies where the environment remains shaped by significant elevations and seasonal water flow.