450 – Tataviam Indians settle in the upper Santa Clara River Valley.

1769 – Portola discovers Newhall Pass.

1800 – El Camino Viejo extended to San Fernando Pass (Newhall Pass).

1842 – Gold rush in Placerita Canyon, first discovery near the Oak of the Golden Dream.

1847 – John C. Fremont marches through Newhall Pass on the way to Cahuenga Pass. Pass renamed Fremont Pass.

September 9, 1850 – California becomes the 31st state.

1852 – Henry C. Wiley builds a windlass system over Newhall Pass.

1854 – Phineas Banning makes a thirty foot deep cut into Newhall Pass.

August 10, 1854 – Fort Tejon established.

December 5, 1854 – General Phineas Banning drives first stage through his 30-foot-deep-cut at Fremont Pass.

1855 – Kern Canyon Gold Rush. Traffic brought to almost a standstill in Newhall Pass.

1857 – General Beale leads caravan of US Government camels through Newhall Pass.

January 9, 1857 – Parkfield/Fort Tejon/Wrightwood earthquake. San Andreas Fault M8.4.

October 21, 1858 – Butterfield-Overland Stage Route is started through Banning Cut and San Francisquito Canyon.

1863 – General Edward F. Beale deepens Banning’s Cut to 90 feet.

1864 – Los Angeles and Fort Tejon Road completed. Runs through San Francisquito Canyon. Fort Tejon abandoned.

June 24, 1865 – San Fernando Mining District founded.

1868 – Surveys looking for a better route over the Liebre Mountains find future Ridge Route alignment to be the best way.

May 12, 1868 – Soledad Post Office established.

June 12, 1868 – Soledad City is officially renamed Ravenna.

1870 – Cedar Mining District founded near Acton.

1871 – Elizabeth Lake School District established.

September 1872 – Sulphur Springs School District founded.

1875 – Soledad Judicial District set up.

January 15, 1875 – Henry Mayo Newhall buys Rancho San Francisco.

1876 – Mentryville founded in Pico Canyon.

July 14, 1876 – San Fernando Railroad Tunnel is completed.

August 12, 1876 – First engine through San Fernando Tunnel.

September 5, 1876 – Golden spike driven at Lang Station.

September 6, 1876 – Newhall Depot opens near Bouquet Junction.

October 1876 – Acton Depot opens.

October 13, 1876 – Newhall is founded at site of present-day Saugus.

February 16, 1878 – Newhall is moved from Bouquet Junction to 6th and Railroad Ave.

Mid 1870’s – First asphalt paving put down in Newhall Pass.

September 1, 1887 – Santa Paula Branch of SP railroad completed.

1887 – Castaic railroad stop opens at Castaic Junction. Saugus founded.

June 21, 1888 – Saugus Station opens.

1888 – Acton Post Office established. Southern Hotel in Newhall burns to the ground.

1889 – Castaic School founded.

1891 – Surrey Post Office established in Saugus. Acton Rooster newspaper established.

1892 – San Gabriel Forest Reserve Established.

1893 – Pico Canyon/Newhall earthquake. Santa Susana Thrust Zone?

1904 – Santa Paula Branch of Southern Pacific Railroad is relegated to a branch line after Coast Route is completed through the San Fernando Valley.

April 18, 1906 – San Francisco earthquake.

1908 – Sterling Borax works begins production. San Gabriel Forest Reserve combined with San Bernardino National Forest to become Angeles National Forest.

1909 – First car travels through Beale’s Cut.

1878 to 1910 – Railroad Avenue is the main street in Newhall.

1910 – Ridge Route is completed through Newhall. Spruce St. becomes the main street. Newhall Highway Tunnel is built to avoid the 29% grade at Beale’s Cut.

1911 – California Highway Commission formed.

1912 – Surveys begin for Ridge Route alignment.

November 5, 1913 – Los Angeles Aqueduct is completed and opened.

July 15, 1915 – Castaic founded.

Late November 1915 – Ridge Route is completed over Tejon Pass.

1916 – Original Santa Clara River Bridge built. Original South Fork Bridge built. State takes over highway through Newhall Pass.

1917 – Castaic Post Office established.

1919 – Newhall Signal newspaper established.

1919-1920 – Ridge Route paved with a 20′ slab of reinforced concrete.

1921 – Mint Canyon Road Completed (Sierra Highway).

1922 – Bonelli Stadium opens. Original Newhall Creek Bridge on San Fernando Road constructed.

1925 – San Bernardino National Forest split from Angeles National Forest – Angeles becomes the western section as it is today.

1926 – US 99 commissioned using the Ridge Route and San Fernando Road. Newhall Community Hospital founded on San Fernando Road.

1927 – Original Placerita Creek and La Placerita Creek Bridges built on San Fernando Road.

1928 – US 99 first signed in California by Auto Clubs.

March 12-13, 1928 – St. Francis Dam collapses washing out original US 99 Santa Clara River Bridge and parts of Piru, Fillmore, Bardsdale, Santa Paula, Montalvo, Saticoy, and Ventura. Kills over 500 people.

February 1929 – Current Santa Clara River Bridge (US 99 (The Old Road)) completed.

Pre-1930 – Ridge Route and Sierra Highway (Mint Canyon Road) are the only way to Newhall.

1930 – US 99 completed through Weldon Canyon (Newhall Alternate). Three lanes wide. Newhall Depot closes.

1933 – Bouquet Dam completed.

October 29, 1933 – Ridge Route bypassed by the Ridge Route Alternate through Piru Gorge.

1934 – Mint Canyon Road (Sierra Highway) straightened through Mint Canyon. State Highways in California first signed. SR-7 is signed on Sierra Highway, San Fernando Road, and Soledad Canyon Road.

1935 – San Fernando Road widened to four lanes through downtown Newhall.

1936 – US 99 full three lanes from Newhall Pass to Grapevine. Saugus Elementary School built.

1937 – US 6 extended to Long Beach, California from Denver, Colorado. SR-7 resigned as US 6 on Sierra Highway, Soledad Canyon Road, and San Fernando Road.

1938 – New Sierra Highway (US 6) bypasses Newhall and Saugus. Newhall Highway Tunnel is eliminated. Sierra Highway from Canyon Country to Newhall built with three lanes. Bridge built over Placerita Canyon Road on Sierra Highway.

1940 – First movie theater in the valley opens as “The American” at Spruce St. and 11th St.

1943 – Grapevine Grade (US 99) widened to four lanes.

1945 – Santa Clarita High School opens. Name changed to Wm. S. Hart High School after he dies.

1946 – First concrete barrier installed on Grapevine Grade (US 99).

1947 – First tract homes built in Seco Canyon. Bonelli Stadium reopens as Saugus Speedway.

1948-1951 – US 99 widened to a four lane expressway from Weldon Summit to Tejon Pass.

1952 – Arvin/Bakersfield earthquake. White Wolf Fault M7.4.

1954 – First segment of the Golden State Freeway built. Begins at the SR-7, US 6, US 99 (Sepulveda Boulevard and San Fernando Road) junction and goes on the present-day truck routes of Interstate 5 to Weldon Canyon.

1957 – Piru Dam is completed.

1960 – Placerita Canyon Road paved from Sierra Highway to Sand Canyon Road. Interstate 5 is signed along freeway sections of US 99.

Pre-1963 – Soledad Canyon Road runs on Valley Canyon Road near Lang Station Road. Rerouted when SR-14 was completed in 1963.Canyon Country area referred to as Solemint.

1963 – New SR-14 Antelope Valley Freeway is completed from Red Rover Mine Road to near Solemint Junction. End of freeway was near present-day Canyon Country Park. US 6 decommissioned from Long Beach to Bishop. Old SR-14 (Artesia Blvd.) renumbered as SR-91. US 91 decommissioned in California. Canyon Country founded.

1964 – US 99 is decommissioned. Signing is not taken down until 1968. First segment of I-5 built in the Santa Clarita Valley. Runs from Saugus Junction north to Castaic Junction.

1967 – Interstate 5 is completed through the Santa Clarita Valley. Construction begins on Castaic Dam. Construction started on Valencia.

1968 – Sierra Highway widened to a four lane divided highway from Soledad Canyon Road to I-5. US 99 signage taken down along I-5 and older alignments. Newhall Depot is destroyed in a fire. Bridge over Placerita Canyon Road removed on Sierra Highway.

1969 – Lang Station is demolished by the Southern Pacific Railroad.

Pre-1970 – Newhall Avenue goes to Magic Mtn. Pkwy (then Saugus and Ventura Road).

February 9, 1971 – Sylmar/San Fernando earthquake. Delay in opening 5/14 interchange due to quake damage.

May 29, 1971 – Magic Mountain opens.

April 30, 1971 – Last Southern Pacific passenger train through Santa Clarita.

December 15, 1971 – Castaic Dam is completed.

1972 – US 99 is fully decommissioned in WA and OR. SR-14 (Antelope Valley Freeway) is completed from Solemint Junction to Interstate 5. “Santa Clarita Valley” becomes official name for valley.

1975 – Santa Clarita Valley Historical Society founded.

1978 – Soledad Canyon Road is widened from Sierra Highway to Sand Canyon Road.

Winter 1983 – Sand Canyon Road Bridge washed out by El Nino floods.

December 15, 1987 – Santa Clarita becomes an incorporated city.

1989 – San Fernando Road widened from Sierra Highway to Newhall. Santa Clarita Post Office dedicated.

1992 – San Fernando Road widened from Magic Mountain Parkway to Hi Chic Curve.

October 26, 1992 – Metrolink Commuter Rail service begins.

1994 – Metrolink service extended to Lancaster after the Reseda/Northridge earthquake. Princessa Station opens in eastern Santa Clarita.

January 17, 1994 – Reseda/Northridge earthquake. 5/14 interchange rebuilt due to quake damage. Santa Susana Thrust Zone M6.8.

January 24, 1994 – Metrolink Santa Clarita Line extended to Lancaster.

1995 – Magic Mountain Parkway is widened at Edison Curve. 5/14 interchange reopens as the Clarence Wayne Dean Memorial Interchange. 1916 bridge over the South Fork replaced.

1996 – San Fernando Road is widened from Newhall to Hi Chic Curve.

May 11, 1996 – Mentryville reopened to the public as a park.

November 1996 – Barn at Saugus Speedway burns.

1998 – Carpool lanes open on SR-14 from San Fernando Road to Sand Canyon Road.

Spring, 1998 – Heavy rains and weak rock caused the partial collapse of Beale’s Cut

March 18, 2000 – Newhall Metrolink station opens.

September 2002 – State Highway 126 from Highway 14 to I-5 is finally relinquished from Caltrans to the City of Santa Clarita.

Reference: click here, Southern California Regional Rocks and Roads!