United States Postal Service 1007 N Sepulveda Blvd, Manhattan Beach, CA90266 This branch of the U.S. Post Office can assist you with all of your postage, mailing and shipping needs. The post office…More is conveniently located two blocks from the busy intersection of Sepulveda and Manhattan Beach boulevards, so lines can get long during peak hours. This location also offers P.O. boxes in several sizes and for various lengths of time. Visit the USPS Web site to find out more about current postage rates, shipping price points and more.