National Historic Landmark status is the highest level of recognition for a historic building, site, structure, object or district. National Historic Landmarks "are historic properties that illustrate the heritage of the United States." As of 2015 there are just over 2,500 National Historic Landmarks. Examples include the White House, Mount Vernon and Monticello.

The National Register of Historic Places is the "official federal list of districts, sites, buildings, structures, and objects significant in American history, architecture, archeology, engineering, and culture." Listing in the National Register is the second-highest form of recognition and may include sites that have significance "to the history of their community, state, or the nation." As of 2015 more than 90,000 historic places are listed, including the roughly 2,500 National Historic Landmarks, which are automatically listed.

As of 2015, there are two (2) National Historic Landmarks and 7 additional (9 total) National Register sites with the Santa Clarita Valley Historical Society's and SCVHistory.com's sphere of interest. Generally, that sphere is coterminous with the Upper Santa Clara River watershed and includes portions of Los Angeles, Ventura and Kern counties — from the Newhall Pass on the south to Piru on the west, up Piru Creek to the Tejon Ranch on the north, following Highway 138 and the San Andreas Fault eastward through the Hughes and Elizabeth Lake communities to the mouth of Soledad Canyon in southern Palmdale, thence back down through Mount Gleason and the western San Gabriels to the Newhall Pass. (Certain outlying areas are included when specific events or individuals tie them to the Santa Clarita Valley, such as the full length of the Los Angeles Aqueduct, the Cerro Gordo silver mines and the San Fernando Mission.)

Santa Clarita Valley's National Historic Landmarks
(Ordered by date of designation)

Well No. 4, Pico Canyon Oil Field
No. 66000212
Date: November 13, 1966
County: Los Angeles
Description: Drilled in 1876 to 376 feet (115 m), this was the first commercially successful oil well in California, producing 25 barrels a day (4 m³/d).

Rancho Camulos
No. 96001137
Date: February 16, 2000
County: Ventura
Description: The home of Ygnacio del Valle, an alcalde of Los Angeles and member of the California State Assembly. The ranch was known as the Home of Ramona because it is likely that the popular 1884 novel Ramona by Helen Hunt Jackson was set there. The novel helped in raising awareness about the Californio lifestyle. It is now a museum.

Additional SCV Sites Listed in the National Register of Historic Places
(Ordered by date of designation)

Fort Tejon
No. 71000140
Date: May 6, 1971
County: Kern
Lebec / 3 miles northwest of Lebec.

Vasquez Rocks
No. 72000228
Date: June 22, 1972
County: Los Angeles
Agua Dulce / Agua Dulce Canyon Road.

Ridge Route
No. 97001113
Date: September 25, 1997
County: Los Angeles
Castaic / Along Old Ridge Route, roughly bounded by Canyon Canyon and Sandberg.

Native American Rock Art Site
Site No.: CA-LAN-540
National Register No. 12000859
Date: October 17, 2012
County: Los Angeles
Angeles National Forest: Agua Dulce vicinity (address restricted).

Native American Rock Art Site
Site No.: CA-LAN-1946
National Register No. 12000860
Date: October 17, 2012
County: Los Angeles
Angeles National Forest: Acton vicinity (address restricted).

Native American Rock Art Site
Site No.: CA-LAN-1258
National Register No. 12000861
Date: October 17, 2012
County: Los Angeles
Angeles National Forest: Canyon Country vicinity (address restricted).

Native American Rock Art Site
Site No.: CA-LAN-441
National Register No. 12000863
Date: October 17, 2012
County: Los Angeles
Angeles National Forest: Castaic vicinity (address restricted).

(A fifth Native American rock art site, CA-LAN-1302 in Asuza, was listed the same day.)

Other National Register Sites of Local Interest
(Ordered by date of designation)

Lopez Adobe
No. 71000157
Date: May 6, 1971
County: Los Angeles
San Fernando / 1100 Pico St.
SCV Connection: Catalina Lopez is the relative of Francisco Lopez from whom we derive the site of the latter's Placerita Canyon gold discovery as we know it. The original adobe home of Geronimo and Catalina Lopez became Lopez Station on Butterfield's Overland Mail Company line. Geronimo Lopez was a Mexican Army messenger who in 1847 delivered the articles of capitulation from Gen. Andres Pico to U.S. Gen. John C. Fremont, effectively ending the Mexican-American War. Geronimo Lopez was a character witness in the 1890 murder trial that resulted from the death of his relative, Dolores Cook. We're unsure exactly how the two men were related. According to Ripley (Part 1), who gets it from Prudhomme, Geronimo (b. September 30, 1828, at Los Angeles, d. April 27, 1921) was a son of Pedro Lopez, mayordomo of the San Fernando Mission. While it's not entirely clear in Ripley, she appears to say Luisa Lopez (Mrs. Luisa Lopez Dunne McAlonan, b. 1856) was sister to Geronimo, daughter of Pedro and granddaughter of Francisco Lopez — which apparently would make Geronimo Lopez a grandson of Francisco. We've got more work to do on that. Per Ripley, Luisa in 1874 married her first husband, Thomas Dunne, the tollkeeper at Beale's Cut, and lived with him in the toll house.

Union Oil Company Building / Santa Paula Hardware Co. Block
No. 86002619
Date: August 14, 1986
County: Ventura
Santa Paula / 1003 E. Main St.
SCV Connection: Lyman Stewart and Wallace Hardison produced oil in Pico Canyon and operated out of Newhall in the 1880s before relocating downriver and establishing the Union Oil Co., in this building in Santa Paula.

Bardsdale Methodist Episcopal Church
No. 86001986
Date: August 28, 1986
County: Ventura
Bardsdale-Fillmore / 1418 Bardsdale Ave.
SCV Connection: Thomas R. Bard, who owned the Rancho San Francisco (western Santa Clarita Valley) from 1865 to 1875, donated the land and some of the funding to establish this church in 1898.

Antelope Valley Indian Museum State Historic Park
No. 87000509
Date: February 26, 1987
County: Los Angeles
Lancaster / 15701 East Ave.
SCV Connection: Dating to the early 1930s, the museum houses 8,000 Native American artifacts including many from cultures in and around the Santa Clarita and Antelope valleys.