The 70-Ft-Tall ‘Chalk Pyramids’ in Kansas Are also an Ancient Graveyard for “Sea Dinosaurs”

The Mysterious Giants of the Kansas Plains

Monument Rocks is one of the most interesting natural formations in Kansas. Those light-colored towers look and feel like chalk, but they’re actually made of microscopic skeletal remains.

Here are more interesting facts about one of the eight wonders of the state.

Born from an Ancient Ocean

About 80 million years ago, Kansas sat beneath the Western Interior Seaway, a 600-mile-wide ocean splitting North America.

Microscopic sea creatures called coccolithophores piled up at a rate of just 0.0014 inches per year, forming 300-foot-deep chalk layers. Today, wind and the Smoky Hill River continue to carve these deposits into 70-foot spires.

When you visit, look for rare greenish streaks in the chalk, caused by ancient volcanic ash.

Contains Prehistoric Fossils

If you’re interested in fossils, you’re going to love Monument Rocks. They’ve found mosasaurs here. It’s 42-foot swimming lizards with double-hinged jaws and plesiosaurs, long-necked predators resembling the Loch Ness Monster.

You might spot pterosaur bones (flying reptiles) and Hesperornis, a toothy, flightless bird. If you’re keen-eyed enough, you’ll see the famous “fish-within-a-fish” fossil showing a 13-foot Xiphactinus that choked on its prey. 

It’s One of the 8 Wonders of Kansas

Monument Rocks became Kansas’ first National Natural Landmark in 1968 and earned its “8 Wonders of Kansas” title in 2008.

Unlike most parks, you’ll find it’s free and open from sunrise to sunset on private ranchland.

As you explore, you’ll walk the same dirt paths used by 19th-century fossil hunters like Charles Sternberg.

Guided Native Tribes and Pioneers

For centuries, Native tribes like the Cheyenne and Sioux used these chalk formations as gathering places during buffalo hunts.

Later, pioneers on the Smoky Hill Trail depended on the spires to navigate toward Colorado goldfields. 

Without them, travelers were in danger of vanishing on the “Starvation Trail,” where some resorted to cannibalism during food shortages.

Look for Names in the Chalk

Speaking of the Starvation Trail, there was very little water and food source here. Travelers were forced to ration supplies, or in the most desperate cases, eat their fellow travelers.

Many carved their names into the chalk, so look for faint 1860s-era engravings. Some of those are from stagecoach passengers on the Butterfield Overland Despatch which often faced raids by local tribes.

Home to Incredible Discoveries

Paleontologists study Monument Rocks to track how sea levels dropped as the Rocky Mountains rose.

In 2024, researchers discovered a rare mosasaur embryo here, proving that these marine reptiles gave live birth.

Visit the Keystone Gallery to see more fossils, including a 6-foot clam shell and preserved sea creatures that lived alongside the dinosaurs.

The View is Always Changing

You’ll see the iconic “Eye of the Needle” arch here, which formed when 19th-century settlers used the rocks for target practice, weakening the chalk. 

Erosion also removes 1–2 inches of rock yearly, so the formations you see will be slightly different from previous visitors’. After spring storms, you might even spot newly exposed fossils.

It’s A Bit Remote

Located 25 miles south of Oakley, you’ll need to drive 6 miles on gravel roads to reach the site. You can pair your visit with Little Jerusalem Badlands (30 minutes east) to see similar formations.

There are no restrooms on-site, but Oakley’s Buffalo Bill Cultural Center offers maps and clean facilities.

Visit the Museum and Try the Tours

Your visit supports local businesses in nearby Oakley and Scott City. Stop by the Fick Fossil Museum to learn more about the region’s fossil history.

Book a sunset horseback tour at a local ranch to hear tales of cattle drives and fossil digs.

If you visit in June, check out Gove County Geology Days, which draws 500+ science enthusiasts from around the country.

A Rare Feature in the Flatlands of Kansas

The pyramids will appear abruptly as you drive, since it’s mostly flatland before it. At night, you’ll see the Milky Way due to zero light pollution.

After a rainstorm, locals say the air smells salty, thanks to ancient sea salts rising from the ground.

Visiting Monument Rocks in 2025

Address: Gove 16, Oakley, KS

It’s open from sunrise to sunset, and there’s no admission fee. From Oakley, take US-83 South 20 miles, turn east on Dakota Road. You don’t need a 4×4, but check for closed roads after storms.
You can also check out Castle Rock (45 mins east) or dig for fossils at Kansas Rocks Park nearby.

Remember that Monument Rocks is located on private property and the roads leading to it are unpaved.