Thornton Quarry

Thornton Quarry is a large limestone extraction site in Illinois that has been actively mining rock over many decades. Today the site serves a dual purpose as a reservoir for Chicago's storm water management system, with major highways running through the land.

The first quarrying operation in this area began in 1836, though the original site was later shut down due to poor quality limestone deposits. The current location evolved over time to become one of the region's major sources of raw materials.

The site reveals traces of an ancient underwater world with coral reef formations that once flourished here. Visitors can observe fossil remains that speak to the area's deep geological past.

The quarry is accessible from major highways, but public access to the active mining area is limited. It is wise to check in advance about visitor opportunities and current site conditions.

A meteorite discovered at this site in 1994 dates back 4.6 billion years to the formation of our solar system. This ancient space rock landed here when the area was submerged beneath coral reef ecosystems.

Location: Illinois

GPS coordinates: 41.57100,-87.62200

Latest update: December 7, 2025 09:20