Gypsum Cave is a limestone cave in eastern Clark County, Nevada, United States, about 15 miles east of Las Vegas, that is listed on the National Register of Historic Places. The cave contains six rooms and is measured at 320 feet long by 120 feet wide. The cave was first documented by Mark Raymond Harrington in a 1930 edition of Scient…Gypsum Cave is a limestone cave in eastern Clark County, Nevada, United States, about 15 miles east of Las Vegas, that is listed on the National Register of Historic Places. The cave contains six rooms and is measured at 320 feet long by 120 feet wide. The cave was first documented by Mark Raymond Harrington in a 1930 edition of Scientific American. Up until about 11,000 BC, Gypsum Cave was inhabited by the Shasta ground sloth.