The United States Postal Service (USPS) is the only organization in the country that regularly delivers to every residential and business address. Committed to providing secure, reliable, and affordable delivery of mail and packages, USPS manages over 30,000 retail locations and processes 47 percent of the world's mail. While the staff at the local Post Office™ in Diamond Bar is generally friendly and accommodating, the facility itself is in need of renovations and modernization. Customers report mixed experiences, with some encountering no issues and others experiencing delays or a sense of disinterest from the staff. Overall, USPS strives to offer a positive customer experience, though the quality can vary depending on the location.
I feel like every time I come here the drive through drop off is closed? Why? Because of this it's so hard to find parking and it gets so congested when you're just trying to drop off a package... Its bad enough that post boxes have tiny holes you can't drop off anything but a thin piece of paper....
February 2026
2/4 430pm: Saw a black female employee taking lunch (in big company truck) outside liferay around the corner and just throwing her trash out the window onto the grass. Disrespectful to the city
January 2026
I got this mail box so my stuff wouldn’t get stolen but I’d rather get it stolen at this point staff loses packages all the time and it takes 3+days to get a package that says it’s already been delivered.
