Formed of Key Largo limestone, or fossilized coral, this land was sold to the Florida East Coast Railroad, which used the stone to build Henry Flagler’s Overseas Railroad in the early 1900s.

After the railroad was built, the quarry was used until the 1960s to produce exquisite pieces of decorative stone called Keystone.

Today, visitors can walk along 8-foot-high quarry walls to see cross sections of the ancient coral and learn about the quarry and its operation, an important part of Florida’s 20th-century history. Samples of the quarry machinery are preserved at the park.

Visitors can enjoy the natural beauty of this island while strolling five short self-guided trails. Picnic tables are available.

The visitor center, which is currently closed, features educational exhibits about the history of this site when open. The park is located at Mile Marker 84.9 on Windley Key near Islamorada.