Places in Castaic Junction carry a Valencia zip code (91355), and it is adjacent to the City of Santa Clarita.

Father Juan Crespí camped near what is now Castaic Junction in 1769, at which time there was a "thriving Indian village" on the site.

[4] The community had an Art Deco−Moderne style train depot, serving the railroad line that ran along the Santa Clara River between Saugus and Piru.

[3][5] Just beyond the north end of the Magic Mountain parking lot is the site of the adobe ranch house for the historic Rancho San Francisco, a Mexican land grant that encompassed the Santa Clarita Valley from Piru to Canyon Country.

[6] According to local legend, icon James Dean ate his last meal at the Tip's Restaurant formerly at the crossroads of Highway 126 and The Old Road before he drove on north.