Yes, depending on the basis of your claim, you may be able to sue the United States Postal Service (USPS). You can’t sue for lost mail, so think about getting insurance if you are concerned about a particular package. You can also send it through certified mail to receive proof that the mail was delivered. But if you are seeking to recover for personal injuries, you can sue the U.S. postal service so long as you follow the proper procedures.
Suing the postal service can be complicated. You need to navigate your way through the Federal Tort Claims Act (FTCA) and, if you don’t do it right, your claim will be barred. So if you are thinking about suing USPS, consider consulting an experienced personal injury attorney knowledgeable about the FTCA.