Chevé Cave
Chevé Cave ( ; ) is a deep cave located in the Sierra Juárez mountain range in the southern Mexico state of Oaxaca. As of 2003, its deepest point has been measured at deep, making it the second deepest known cavern in the Western Hemisphere and the world’s 12th deepest cave. The cave's deepest known point is nearly one vertical mile and seven horizontal miles from the entrance, ending in a terminal sump. The present limit of exploration in Chevé, at 9.3 kilometers from the nearest entrance, represents one of the most remote locations ever attained inside any cave on Earth. The logistics of reaching this point are enormous: more than two kilometers of rope need to be rigged and three underground camps established. Chevé is the deepest proven freshwater hydrological system in the world. Temperatures in Chevé are moderate, ranging from . It has been most thoroughly explored under the leadership of caver Bill Stone.
Ellison's Cave
Ellison's features a number of underground vertical pitches including the two deepest pits in the continental United States: Fantastic (586 feet) and Incredible (440 feet). These two pits lie on opposite sides of the cave. Nearby and parallel to Fantastic are Smokey I (500 feet), Smokey II (262 feet), and other extremely deep pitches. There are over 7 routes to reach the bottom level of the cave from the Fantastic side. Fantastic and Smokey I both extend to TAG Hall, a passage at the bottom of the cave. To reach Fantastic, or the large pits on the Fantastic side, cavers must also descend the Warm Up pit (125 feet).