The San Luis Hills are a geologically unique landform of the southern San Luis Valley, rising over 1,000 feet above the valley floor. They are a remnant of the volcanic deposits that form the San Juan Mountains and underlay the depositional soils of the valley. Desert grasslands with sagebrush and prickly pear cactus characterize the slopes and mesas of the area. Small stands of pinyon pine and juniper are present, mostly on the southern and eastern portions of the mesa top. The unnamed summits provide a panorama of the river systems, landforms, and ecosystems of the valley.