Post Offices in Santa Clarita, California, United States SearchSearch SearchSearch View: Grid 1View: Grid 2View: Grid 3View: Grid 4View: Grid 5View: List Castaic Post Office No Reviews Favorite Fax: (661) 775-7199Phone: (661) 775-7166Retail Hours Santa Clarita Post Office No Reviews Favorite Fax: (661) 254-7318Phone: (661) 254-3270Retail Hours