Pompey’s Pillar: Montana Landmark at a Crossroads of Western History

Pompey's Pillar National Monument

Pompey’s Pillar, near Montana’s magnificent Yellowstone River, first came into history when William Clark of Lewis and Clark fame carved his name there.

On Nov 5, 1805, the Lewis and Clark expedition finally caught a glimpse of the mighty Pacific Ocean. “O the joy!” wrote an excited William Clark. Clark and his co-leader Meriwether Lewis had not found an easy all-water route to the Pacific as President Thomas Jefferson had hoped. They had, however, been the first Americans to scientifically and methodically explore what was later called the “great American West.” They discovered new species of plants and animals, and mapped their route across a continent. Pompey’s Pillar contains the only physical evidence of that justly celebrated epic journey.

Lewis and Clark’s Journey Back to the United States

William Clark’s inscription on Pompey’s Pillar.

The Lewis and Clark expedition—formally the Corps of Discovery—settled down for a somewhat wet and bleak winter of 1805-1806. The Pacific Northwest is notorious for its rain, and the explorers, seasoned through they were, were sodden and uncomfortable.

There was always an outside chance that they could “hitch a ride” with one of the American merchant ships that came to trade with the Indians for furs. In fact, the very river they had travelled—the Columbia-was named after an American vessel that visited the area in 1792.

But no ship appeared, so the expedition would have to more or less retrace their steps back some 2,000 miles to the United States. But in July, 1806, Lewis and Clark decided to divide the expedition in order to explore more new territory.

Lewis took a party and rode on horseback to the Maria’s River region, while Clark and his men went by canoe down the Yellowstone River, first going through th Bozeman Pass. Lewis and Clark intended to reunite at a later point.

Pompey’s Pillar

Clark and his party stopped near a curious sandstone formation near the river.. It was—and is—curious because it sticks out like “a sore thumb,” with nothing else around the immediate vicinity. The National Park Service’s Pompey’s Pillar website quotes Clark’s journal extensively. “At 4 pm,” Clark wrote, “(I) arrived at the remarkable rock situated in an extensive bottom. This rock I ascended, and from it’s top had a most extensive view in every direction…” Then, Clark continues, “This rock, which I shall call Pompey’s Tower, is 200 feet high… and only accessible from the N.W.”

Nicholas Biddle, the first editor of Clark’s journals, changed the name from “tower” to “Pillar” some years later. But the “Pompey” refers to Jean Baptiste Charbonneau, infant son of Sacagawea. “Pomp” was Clark’s affectionate nickname for the child.

Captain Clark then carved his name and date on the rock, which still survives today. Given its age, and the chance of damage by time, erosion, or vandals over the years, its preservation is remarkable. The inscription reads “WM Clark, July 25, 1806.” Another curious feature was that the explorer didn’t “print” the letters in the rock, but “handwrote” them instead. It must have been a much harder thing to do.

The Pillar and the Seventh Cavalry

In 1873 the Pillar had another brush with history. Troopers of George Armstrong Custer’s famed 7th Cavalry stopped by the Pillar for a swim in the Yellowstone River, when suddenly they were fired upon by Lakota Sioux Indians. Three years later there would be a much deadlier confrontation at the Little Bighorn.

Pompey’s Pillar National Monument

The Pillar was in private hands for many years, but finally in 2001 the Pompey’s Pillar National Monument was created. The pillar is a sandstone butte about 150 feet tall, and covering about two acres at the base. A wooden platform enables visitors to view Clark’s signature, which is protected by glass. The monument is only about 25 miles east of Billings, Montana.


  1. Stephen E Ambrose, Undoubted Courage: Meriwether Lewis, Thomas Jefferson, and the Opening of the American West (Simon and Schuster, 1997)