The Chicago Department of Aviation has narrowed more than 2,900 entries to six finalist names for the 50-ton dolostone boulder unearthed beneath O’Hare International Airport. Public voting runs through 5 p.m. Central on Monday, November 2, 2026, and the winning name will appear in a boulder exhibit at the airport.

Key Takeaways

• The six finalists are Sweet Stone Chicago, No ORDinary Rock, Chicago Rocks, O’Rock, Orchard Rock, and Da Rock.
• Public voting by online ballot closes at 5 p.m. Central on November 2, 2026.
• The boulder measures 11.5 feet wide, 8 feet deep, and 7.5 feet tall, and weighs about 50 tons.
• Crews found it on June 16, about 30 feet below the airfield, while digging a stormwater basin for the ORDNext expansion.
• The rock is dolostone, Illinois’ official state rock, formed roughly 400 million years ago.
• The winning name will be featured in an exhibit outside O’Hare’s Multi-Modal Facility.

Chicago Narrows Nearly 3,000 Ideas to Six Names

The Chicago Department of Aviation launched the naming contest in September, and the response outran the plan. The department originally said it would select five finalists, then advanced six after reviewing more than 2,900 submissions.

The finalists lean into Chicago identity and airport wordplay. No ORDinary Rock borrows O’Hare’s ORD airport code, Orchard Rock nods to Orchard Field, the airport’s original name, and Da Rock brings the city’s accent into the mix. “We’ve chipped away at that list to reach six finalists,” said Aviation Commissioner Michael McMurray.

Before the contest, airport staff had informally been calling the stone the “O’Hare bean,” a name many Chicagoans will hear as a nod to Cloud Gate in Millennium Park. That nickname did not make the final ballot. Neither did Rocky McRockface, the kind of entry that has made public naming contests a running joke since Boaty McBoatface.

The O’Hare Boulder Surfaced During the ORDNext Expansion

The O’Hare boulder came out of the ground during excavation of the South Detention Basin, a stormwater management facility built as part of ORDNext, the largest terminal expansion in O’Hare’s history. Excavator operator Ron Pitelka unearthed it on June 16, working about 30 feet below the airfield’s surface.

Rather than haul it away as construction debris, the Chicago Department of Aviation preserved and relocated it, turning a single rock into the most visible public symbol of a project that is otherwise measured in gates, square footage, and years of construction. The changes around O’Hare extend beyond the terminal work, including a proposal from business leaders for a $2.25 billion O’Hare Flyer express train with 15-minute downtown service.

Pitelka put the find in perspective when the contest launched. “Long after I’m gone, that boulder is still going to be there,” he said.

Dolostone Connects the Boulder to Illinois’ Ancient Past

A geologist working on the ORDNext project identified the boulder as dolostone, a sedimentary carbonate rock made mostly of the mineral dolomite, or calcium magnesium carbonate. Dolostone is closely related to limestone. It can form when magnesium-rich groundwater moves through limestone or lime mud and replaces calcium in the rock with magnesium.

Dolostone is the hard bedrock that lies beneath most of Illinois’ glacially deposited soil, which is part of why it was named Illinois’ official state rock. The rock in O’Hare’s boulder formed during the Silurian period, about 400 million years ago, when the land that is now Chicago sat in a warm, tropical environment.

That history gives the naming contest a quieter significance. The boulder is a rare, visible piece of the bedrock that much of the region sits on, brought to the surface by one of the largest construction projects in the city.

The Boulder Joins Chicago’s Naming Contest Tradition

Chicagoans have grown used to naming city equipment. The Department of Streets and Sanitation’s snowplow naming contest has produced winners such as “Mrs. O’Leary’s Plow,” “Sears Plower,” and “CTRL-SALT-DELETE.” The boulder contest borrows that playful format but attaches it to something permanent.

Once voting closes, the winning name will be announced on O’Hare’s social media channels and displayed with the boulder in its exhibit outside the airport’s Multi-Modal Facility.

 

FAQs

What Is the O’Hare Boulder?

The O’Hare boulder is a 50-ton dolostone rock found about 30 feet below O’Hare International Airport’s airfield in June 2026. Crews uncovered it while excavating a stormwater basin for the ORDNext expansion project.

How Is the O’Hare Boulder’s Name Being Chosen?

The Chicago Department of Aviation selected six finalists from more than 2,900 public submissions. The public picks the winner through an online ballot that closes at 5 p.m. Central on November 2, 2026.

What Type of Rock Is Dolostone?

Dolostone is a sedimentary carbonate rock made mostly of the mineral dolomite, or calcium magnesium carbonate. It forms the hard bedrock beneath much of Illinois.

What Is the Difference Between Dolostone and Limestone?

Limestone is made mostly of calcium carbonate, while dolostone contains magnesium as well. Dolostone can form when magnesium-rich groundwater passes through limestone and replaces some of its calcium with magnesium.

Is Dolostone the Illinois State Rock?

Yes. Dolostone is Illinois’ official state rock, reflecting its role as the bedrock beneath most of the state’s glacially deposited soil.

Where Will the O’Hare Boulder Be Displayed?

The boulder will be featured in an exhibit outside O’Hare’s Multi-Modal Facility, along with its winning name. The name will also be announced on O’Hare’s social media channels.