steep descent. Passengers debarked and walked. The outbreak of the American Civil War in 1861 disrupted mail service along the Butterfield Overland Mail's southern stagecoach route from St. Louis, Missouri via El Paso, Fort Yuma and Los Angeles and on to San Francisco via the Tejon Pass, which had begun its run in 1858. To compensate, the government contracted the Butterfield Company to carry mail between Los Angeles and San Francisco via the new wagon road over the Santa Susana Pass. The first overland mail stage run through the pass took place on April 6, 1861. The main route climbs through what is now Santa Susana Pass State Historic Park, with a branch in L.A. City Park 'Chatsworth Park South.' It was an important artery linking the Los Angeles Basin and inland Ventura County, and was part of the main route for travel by stagecoach between Los Angeles and San Francisco from 1861 until the opening of rail traffic between the cities in 1876. The Old Santa Susana Stage Road is listed on the National Register of Historic Places. Part of the stage road is also a Historic-Cultural Monument of Ventura County and of the City of Los Angeles under the name 'Old Stagecoach Trail.' Late 19th and 20th century A new wagon route bypassing the deteriorating Devil's Slide was opened in 1895 to the north . Initially called El Camino Nuevo (the New Road), it was later named the Chatsworth Grade Road, which continued in use until Santa Susana Pass Road (now Old Santa Susana Pass Road) was built in 1917. This was the first automobile route between the San Fernando and Simi Valleys. It also was the main northbound 'coast road' to Santa Barbara and San Francisco, until the Conejo Grade in Ventura County between Conejo Valley and the Oxnard Plain on "Camino Real Viejo" (the Old Royal Road, now U.S. Route 101), was improved. In 1968 State Route 118, the "Simi Valley–San Fernando Valley Freeway" opened, north of the old auto road as the latest route across the Pass. In 1994 it was renamed the "Ronald Reagan Freeway". The pass area became famous from being seen in many movies, primarily Westerns, filmed from the 1920s to the 1950s here at the Spahn, Iverson, Bell Moving Picture, and Corriganville Movie Ranches. The area became infamous in the late 1960s with the Manson Family headquartered at the Spahn Ranch,