O'Neil Pass is a mountain pass at an elevation of 2.037m (6,683ft) above the sea level, located in Lawrence County, South Dakota, in United States.
Located within the Black Hills National Forest, the road to the summit is paved. It’s called Canam Highway, part of the U.S. Route 85. It’s one of the highest roads in all of South Dakota.
The pass is 18.4 miles long running between the towns of Buckhorn (Wyoming) and Cheyenne Crossing (South Dakota). Watch for wildlife. It can be very dangerous in winter months, with ice and snow on the winding road. Just past the pass, you'll find Trailshead Lodge, a year-round lodge offering cabins and snowmobiling.