California's 45th congressional district

Foothill Ranch is a master planned community in Orange County, California, United States. The population was 10,899 at the 2000 census. Foothill Ranch was incorporated into the city of Lake Forest, California, in 2000. Prior to that, it was a census-designated place. Foothill Ranch is notable for companies such as Oakley, Inc., Nike, Kaiser Aluminum, Kawasaki, Hampton Products/Brinks, TAE Technologies, Viking Technology, Image Options and ProBoards. It is also the home of Saddleback Church.

Modjeska Canyon is an unincorporated community on the western slope of the Santa Ana Mountains in eastern Orange County, California. It is a suburban community of several hundred residents, with a small park and a volunteer fire station. The ZIP Code is 92676, and the community is inside area code 714.The canyon is also the location of the Tucker Wildlife Sanctuary. Most of the canyon is bordered by the Cleveland National Forest. The community of Modjeska is very tight knit, hosting several in-canyon events, such as pot lucks, dance lessons, movie nights at the park, Fourth of July parades, as well as Christmas and Halloween parties. The parties are usually held in the Modjeska Community Center and the Fire Station. They also hold events for non-residents to come and enjoy, such as an arts and crafts fair held in early spring at the Tucker Wildlife Sanctuary.

The Irvine Ranch Natural Landmarks (also known collectively as Irvine Ranch Open Space) are a collection of protected areas in Orange County, California in and around Irvine. They encompass almost 50,000 acres (20,000 ha) of land which was once a part of the Irvine Ranch owned by the Irvine Company. Almost 40,000 acres (16,000 ha) of the landmarks were designated a National Natural Landmark in 2006 and a California Natural Landmark in 2008.Irvine Ranch contains a remarkably complete stratigraphic succession ranging in age from late Cretaceous (80 million years ago) to the present. The primary biological features at the site include coastal sage scrub and chaparral communities, including rare Tecate cypress woodlands.

Williams Canyon is a census-designated place (CDP) in the canyon of the same name in Orange County, California, United States. It is located in eastern Orange County on the western side of the Santa Ana Mountains, south of Silverado and north of Modjeska. Most of the community is within Cleveland National Forest. It was first listed as a CDP prior to the 2020 census.

Carbondale, in Orange County, California, is a historical coal mining town in Santiago Canyon, where Santiago Creek had its confluence with Silverado Creek in Silverado, California. It had a post office from May 11, 1881, to January 29, 1884, when it was closed and mail sent to the Santa Ana post office.Coal was discovered near Santiago Creek in 1878. A coal mine was established there, called the Santa Clara. In 1881, the Southern Pacific took over the Santa Clara Coal Mine, and a mining camp, Carbondale, with a post office was established on the flat near the creek. Besides the post office, it had a hotel, saloons, a store, and shacks for the miners. Carbondale became the post office for Silverado after its post office was closed on January 22, 1883. When the coal was depleted, the coal mine was closed down in 1884. Carbondale's post office closed, and its buildings and equipment were removed, leaving few other remains.

The Frank R. Bowerman Landfill is a landfill in the western Santa Ana Mountains, in Orange County, California. It opened in 1990. The landfill is located between Limestone Canyon Regional Park and State Route 241.It is one of the largest landfills in California and the ninth largest in the United States. It contains an estimated 31 million tons of waste.

The Santiago Fire was a wildfire located near Santiago Canyon in Orange County, California, U.S., and one of thirty California wildfires of October 2007. The fire was intentionally started.

Modjeska House, also known as Arden, is a house designed by Stanford White in Modjeska Canyon, California. It is significant for being the only surviving home of Helena Modjeska, a Shakespearean actress and Polish patriot. The property is located in a live oak grove on the banks of Santiago Creek in Modjeska Canyon, California.

Etnies Skatepark of Lake Forest (stylized as etnies Skatepark) is a public skatepark located in Lake Forest, California, United States. It is the largest free skatepark in the state, with an area of over 62,000 square feet (5,800 m2). The skatepark is owned and operated by the City of Lake Forest. The skatepark provides free identification cards for residents of Lake Forest and Foothill Ranch, while a $15 fee is required for non-residents in exchange for the identification card. Helmets, knee and elbow pads are required for all users. Spectators, with the exception of permitted photographers, are not allowed inside the park.

Silverado is an unincorporated community in Silverado Canyon, which is located in the Santa Ana Mountains in eastern Orange County, California. Portions of the town sit on a former Mexican land grant Rancho Lomas de Santiago. Silverado is located at the boundaries of Cleveland National Forest. The site is a California Historical Landmark,

Portola Hills is a district in the city of Lake Forest, California in Orange County, United States. It was formerly an unincorporated community and census-designated place before it was annexed into Lake Forest in 2000. The population was 6,391 at the 2000 census. Portola Hills lies near Whiting Ranch Wilderness Park and Cleveland National Forest. Foothill Ranch is to the west, Rancho Santa Margarita in the southeast, Mission Viejo in the south, and the unincorporated regions of Silverado and Santiago Canyon to the north and northeast.

Tucker Wildlife Sanctuary is a non-profit nature reserve on the Santa Ana Mountains in Orange County, California, in the United States. It is located near the end of Modjeska Canyon, at the foot of Modjeska Peak, and adjacent to the Cleveland National Forest. The Sanctuary is owned and operated by the Environmental Nature Center (ENC). The nearest community is the city of Lake Forest. The Sanctuary serves as a research center for California State University, Fullerton students, faculty and others. Tucker is open to the public to enjoy and learn about the local wildlife and natural habitat in the Southern California canyon area.Tucker's facilities include a small natural history museum and interpretive center, two ponds, a bird observation porch and feeders, relaxing patio and picnic areas, a small amphitheatre, a caretaker's house, hiking trails, a gift shop, restrooms and a visitor parking lot.