Pompeys Pillar and the Lasting Signature of William Clark

Pompeys Pillar National Monument is not only a scenic picture taking stop on your western U.S. road trip but it also offers the visitor an opportunity to see what physical remnants remain of the great American westward exploration and migration..



 Pompeys Pillar

Yellowstone Watershed,Courtesy Shannon1

Located in south central Montana, 28 miles east of Billings off Interstate-94, the sandstone butte which is Pompeys Pillar is one of the most famous sandstone buttes in America.

 It was a significant Lewis and Clark discovery. The Lewis and Clark Expedition from 1803-1806 was commissioned by President Thomas Jefferson and was America's first exploration to the Pacific Coast.

Part of the expedition's goal was to ascertain the available resources in this region that had been acquired with the Louisiana Purchase. It was at this site that Captain William Clark carved his name in July of 1806 while returning from his expedition to the Oregon country. Today's western U.S. tourist can see the signature just as Clark etched it over 200 years ago. Actually, many other historic figures from the 1800's also observed the signature such as the famous steamboat pilot Captain Grant Marsh while maneuvering the steamboat Josephine up the Yellowstone River. Captain Marsh gained fame as the pilot of the steamboat Far West during the Battle of the Little Bighorn. Marsh set a speed record while returning down the Missouri with wounded cavalrymen.

Also, in 1873 Lt. Col. George Armstrong Custer camped with his troops opposite the Pillar. The first official observation of Clark's signature was reportedly in 1863 by James Stuart, a Montana pioneer and prospector. In addition to the Native American pictographs and William Clark's signature there are hundreds of other initials carved into the rock including many early pioneers who journeyed by.

Independence Rock in Wyoming is another historic site with names and initials carved in during America's westward migration. Initials carved cover a wide variety of travelers including fur trappers, railroad workers, missionaries, army troops and settlers. At Pompeys Pillar, a walkway of about 200 steps takes you to the upper part of the tower where you can see Clark's original signature. The signature is preserved behind a brass and glass case to protect it from the effects of nature. Pompeys Pillar was and is a very impressive as William Clark's journal entry describes the site as “remarkable rock” with its “extensive view in every direction.

As many historians know, the Lewis and Clark journals describe the expedition very well. Among some very interesting Lewis and Clark journal entries is the group's encounter with Montana Grizzly Bears. While at first they noted how easy it was to bring down the giant animal with a rifle, later journal entries describe how the beast chased them into rivers and up trees.

Pompeys Pillar location at a natural ford on the Yellowstone River, along the Lewis and Clark route, and being the only major high outcropping in the area made Pompeys Pillar a popular landmark. Historians believe that native peoples have used Pompeys Pillar as an observation point for over 11,000 years.

Naming the Site

Clark's signature at Pompeys Pilla

William Clark originally named the site Pompeys Tower but the name was changed to Pompeys Pillar after Nicolas Biddle wrote an account of the Lewis and Clark expedition. Clark named the Pillar for young Baptiste Charbonneau who he had nicknamed "Pompy", the infant son of Sacagawea who was a Shoshoni woman accompanying the expedition. Lewis and Clark left few reminders on the land as they traveled west. William Clark’s engraved signature on Pompeys Pillar is one of them.

Land of the Crow Indians

For many centuries this rock outcropping which rises about 150 feet from the banks of the Yellowstone River served as an important landmark to the local native people. The Crow Indians used the Pillar as a prayer site. The Crow Indians called the Pillar the place where the Mountain Lion lives. There is a natural head of a lion in the sandstone on the north face of the Pillar. The Yellowstone Valley has long been considered the heart of Crow Country. Many historians believe that the original location of the Crow were at the headwaters of the Mississippi River. Some others think the Crows may have come from Manitoba. What is known is that they settled in southern Montana. The Crow were pushed westward by the influx of the Sioux. The Sioux themselves were pushed west by American westward migration.

A National Monument

Crow Indians, circa 1880

The organization which can be said was responsible for Pompeys Pillar becoming a National Monument was the Pompeys Pillar Historical Association. According to the Association, their mission statement is.. "To develop the historic potential of Pompeys Pillar National Monument, the site of the only remaining physical evidence on the trail of the Lewis and Clark Expedition of 1803-1806". Another very interesting nearby site is Guernsey Lake State Historic Park in Wyoming where excellent remnants of Oregon Trail wagon wheel ruts can be seen.

The site was named a National Historic Landmark in 1965 and then became a National Historic Monument in 2001. Pompeys Pillar Interpretive Center opened it's doors in 2006. Exhibits on display in the 5,700 square foot center relate to the Lewis and Clark Expedition and the entire detachment.

Here you will find a very large amount of Lewis and Clark information. The Montana Lewis and Clark route is detailed very well at the interpretive center. The center also showcases native culture, flora and fauna. A side trip to Pompeys Pillar National Monument during your next western vacation would be a fun, low cost and highly educational stop for the entire family.


The monument is located northeast of Yellowstone National Park. Use exit 23 off Interstate-94. You can also reach Pompeys Pillar on State Hwy 312. It's a picturesque vacation stop with many good photo opportunities.

(Photos from the public domain)