Red Rock Coulee Natural Area

Red Rock Coulee Natural Area is a protected geological site in southeastern Alberta, Canada. The area is renowned for its remarkable reddish sandstone concretions—spherical rock formations that are the largest of their kind in Canada, measuring up to 2.5 metres in diameter.

These concretions formed millions of years ago in ancient seabed deposits and have been exposed through erosion of the surrounding softer shale. The distinctive red-brown colour comes from iron oxidation.

The area is also notable for being rattlesnake habitat—visitors are advised to watch their step.