Pioneer Historic Byway

Starting in Franklin, Idaho’s first city, the Pioneer Historic Byway follows the path of early pioneers along parts of the Oregon Trail. The route meanders along Bear River to the first Yellowstone route, revealing Mormon settlements and historic military campaigns along the way. Attractions include Red Rock Pass, Niter Ice Cave and Soda Springs.

The route passes one of the original Yellowstone Highway markers, a century-old Mormon Oneida Academy, and the first gristmill in Idaho. These historical points, along with major geologic and military sites, speak to the first settlements in Southeast Idaho. Located in southern Bannock County, south of Downey, Red Rock Pass is a low mountain pass that holds some geologic secrets. As the spillway of ancient Lake Bonneville, this pass sits between two mountain ranges—the Portneuf to the east and the Bannock to the west. It was cut through resistant shale, limestone, and dolomite and takes its name from the red limestone seen on bordering cliffs.

Rumored to be used by John A. Dalton and his family, a refuge from rival Native Americans in the area, Niter Ice Cave is now a roadside attraction. The cave was formed from lava flows eons ago and hosts a lava field in the middle of a flat field. Just a few miles from Grace, Niter Ice Cave is a must for families and adventurers. It is a popular destination for spelunking.

The byway passes through Soda Springs, named after hundreds of natural springs of carbonated water located in and around the city. The springs were a famous landmark along the Oregon Trail in the mid-19th century. The city is also known for Soda Springs Geyser, which was unintentionally unleashed in 1934 by town leaders who wanted to create a hot pool. Instead a geyser was released when they drilled into a chamber of highly pressurized carbon dioxide gas and cold water. The geyser is now released every hour, showing off a consistent height and volume that shows no signs of ebbing.

Situated in the foothills of Portneuf Valley, Chesterfield was established in 1880 and is now known as a Mormon ghost town. The town was developed by Chester Call, who was looking for grazing land away from Salt Lake City. Most of the historic homes have been restored to their original state. A tour of the Pioneer Historic Byway honors the footsteps of early emigrants along the first Yellowstone route.

Begins at the Utah state line and follows US 91, then Idaho 34, north to US 30 and then east to Soda Springs where it meets the Oregon Trail-Bear Lake Scenic Byway. From there, north on Idaho 34 toward the Wyoming state line.