Keystone, SD is a one street town. So why take the kids? Here are four reasons. 1. Keystone is home to Mount Rushmore. 2. It is a great base for visiting Black Hills attractions. Keystone sits within Black Hills National Forest. Crazy Horse Memorial is just round the bend. Jewel Cave National Monument, Custer State Park, Wind Cave National Park and the gold camp of Deadwood are within 30 minutes of this small town. 3. Remnants of Keystone's gold mining past are found within the city limits. Tour the Big Thunder Gold Mine. Take a 2-hour train trip on the historic 1880 Train. 4. Keystone boasts several family friendly hotels. Many of which have pools!