Nearly 40,000 acres of open space on the historic Irvine Ranch have been designated a Natural Landmark by both the State of California and the U.S. Department of Interior. This honor recognizes the exceptional value of these lands to California and the entire nation. The open space of the Natural Landmark is part of the 50,000 acres of open space preserved on The Irvine Ranch.

The land first received national recognition in 2006 when most of the protected areas on The Irvine Ranch were singled out for their rare biological and geological features through designation as a National Natural Landmark (NNL). NNLs are designated by the U.S. Secretary of Interior for natural areas in both public and private ownership. They are recognized as outstanding examples of the natural heritage of the country alongside national parks, recreation areas and monuments. Nationwide, fewer than 600 sites have received this special designation.

Most recently, on Earth Day 2008, nearly 40,000 acres was designated the first California Natural Landmark (CNL), under a new state program that officially recognizes extraordinary examples of natural resources.

The Irvine Ranch Natural Landmarks contain large areas of important natural habitats and unusual geological formations. It is also home to hundreds of species of plants and animals, including eagles, badgers, mountain lions, Tecate cypress trees, and many rare species of birds, reptiles, amphibians and plants. Scientists have identified this region as one of the world's biodiversity “hot spots” —an area with large concentrations of species found nowhere else.

Both Natural Landmark designations were given only after the land received a rigorous scientific evaluation. The review process considered the diversity and rarity of the area’s biological, geological and paleontological features; its natural communities; the qualitiy of its habitats and the presence of rare, threatened or endangered species – as well a the land’s value for science and education.

The open space on The Irvine Ranch contains rock formations and fossils that reveal a sequence of events chronicling earth's history dating back nearly 80 million years. This landscape also contains large swaths of coastal sage scrub, a rare habitat found only in coastal Southern California and northern Baja California. The combination of unusual geological and rare biological characteristics is rare even among Natural Landmarks.

The Natural Landmark is protected and maintained by group of cooperating landowners including the County of Orange, the City of Irvine, The Irvine Company, The Nature Conservancy and California State Parks. It represents one of the few places in Southern California where habitats have been preserved stretching from the mountains to the sea.

For more information on the National Natural Landmarks program, administered by the National Park Service, visit www.nature.nps.gov/nnl. The California Natural Landmarks program is overseen by California State Parks, http://www.parks.ca.gov/.

Geologists who studied The Irvine Ranch for the Natural Landmark designation identified many unique and rare features - including fossils of hadrosaurian, or "duckbilled," dinosaurs in the Blind Canyon area. On a larger scale, the land is an outstanding illustration of the complicated and unique geologic history of the southwestern continental margin of North America. The exceptionally wide spectrum of rock types and fossils exposed on the land captures changing landscapes and evolutionary events with remarkable completeness for a span of 80 million years. The terrain ranges from picturesque coastlines subject to modern erosion and other natural processes, to rugged, uplifted mountains where the geologic history of Southern California from the late Cretaceous period (65 million to 80 million years ago) to the late Pleistocene period (less than 1 million years ago) is beautifully exposed and largely intact.

Rare and biologically rich coastal sage scrub and chaparral natural communities are the primary features that make the land worthy of Natural Landmark designation. Embedded within the expanses of scrub are imperiled natural communities such as native grasslands, stream corridors and live oak woodlands, as well as important populations of rare and endangered plants and animals. Much of the coastal sage scrub habitats are healthy and relatively undisturbed, and the Landmark is one of the largest areas of this highly threatened Mediterranean-type shrubland remaining in California.

There have been many scientific studies of the geological and ecological resources on The Irvine Ranch in the last few decades. But the comprehensive review and evaluation leading to the Natural Landmark designation is the most rigorous, objective and independent scientific study to date. Findings of the seven accomplished scientists who participated in this review confirm and reinforce previous evaluations recognizing the importance of the open space.
The process for evaluation included a detailed application prepared by LSA Associates, Inc. in Irvine, California. The exhaustive review included onsite evaluations conducted by independent biologists and geologists selected by the National Park Service. These experts produced an extensive report that was then peer-reviewed by seven other independent scientists. Based on these evaluations, and the recommendation of the Science Advisory Committee of the National Park Service, the National Park Service Advisory Board, and the National Park Service director, the Secretary of the Interior designated the Irvine Ranch National Natural Landmark in 2006. A similar review led to the designation as a California Natural Landmark on Earth Day 2008 by the California State Parks director.