Limestone Canyon Regional Park

Limestone Canyon Regional Park is a public regional park in southern Orange County, California under the management of OC Parks. The 4,000 acre park is a part of the Irvine Ranch Open Space, a designation of preserved natural landmarks in Southern California. The premises is near Santiago Canyon and at the foothills of the Santa Ana Mountains, making it a neighbor to the Cleveland National Forest. The park is just outside of the cities of Lake Forest and Irvine and is accessible via County Route S18. Limestone Canyon borders Whiting Ranch Wilderness Park, another regional park in the area. The region was privately owned by The Irvine Company until it was donated to the county in June 2010, along with 20,000 acres of what was Irvine Ranch.

As its name suggests, Limestone Canyon Regional Park is known for its limestone cliffs and oak woodland environment that fills the canyon floor. Locally known as "The Sinks", the landform has been heralded as a "mini Grand Canyon". The site is commonly utilized by hikers and mountain bikers.