Mount Holly Springs Main Office 16 W Pine St 1-800-ASK-USPS Website ( http://www.usps.com/ ) Regular Business Hours: Week Days 08:00AM-04:30PM Saturday 08:00AM-12:00PM Latest Collection at Post Office: Week Days 04:25PM Saturday 03:15PM Phone: 1-800-ASK-USPS For TTY service for the hearing impaired only, 1-877-877-7833