Although the route will take you slightly out of the way, take I–94 on your way to Hardin and stop at Pompey's Pillar National Monument, the only on-site physical evidence of the Lewis and Clark expedition. When William Clark saw this small sandstone mesa rising out of the prairie along the Yellowstone River on July 25, 1806, he climbed to the top to survey the area and then marked it with his signature and the date. His graffiti, along with other engravings by early-19th-century fur traders and homesteaders, is still visible. You can climb to the top of the mesa and view the signature year-round during daylight hours. Festive "Clark Days" are held the last weekend in July, the anniversary of the explorer's visit to the knob. To get to Hardin, continue east on I–94 for a few miles and then head south on Highway 47.
I–94, 25 mi east of Billings, Billings, Montana, 59064, United States