Six Flags Magic Mountain, formerly known simply as Magic Mountain, is a 262-acre (106 ha) theme park located in unincorporated Los Angeles County, California, near the Valencia neighborhood of Santa Clarita, 35 miles (56 km) northwest of downtown Los Angeles.
It opened on May 29, 1971 as a development of the Newhall Land and Farming Company and Sea World Inc. In 1979, Six Flags purchased the park and added the name "Six Flags" to the park's name.
With 19 roller coasters, Six Flags Magic Mountain holds the world record for most roller coasters in an amusement park. In 2017, the park had an estimated 3.3 million visitors, ranking it sixteenth in attendance in North America.
When the park opened, there were 500 employees and 33 attractions, many of which were designed and built by Arrow Development Co. which designed and built many of the original attractions at Disneyland.
According to en.wikipedia