Welcome to Idaho's Mammoth Cave Online Idaho's Mammoth Cave is located at the same location as the Shoshone Bird Museum of Natural History, located 8 miles north of Shoshone, Idaho, on scenic state highway 75. Summer hours are 9 a.m. to 6 p.m., 7 days a week. Idaho's Mammoth Cave and Museum admission rate Adults, $10.00 16 and under, $5.00 6 and under, Free After September 15th, each year, we will open for groups of 8 or more. For more information or to make an appointment, contact us at: (208) 539-7072 or (208) 886-7072 There is a good trail and propane lanterns are provided. If you have flashlights they are always good to bring along. Wear a light jacket. The self guided tour takes about 1/2 hour. You walk about 1/4 mile in and 1/4 mile out. We hope to extend the trail another 1/4 mile in the near future.