There are 17 United States Postal Service post boxes and offices available to the public in St. Clair County. You can use any one of these locations to mail your letter or package via USPS. For additional collection boxes in neighboring communities, see the list of mailboxes in Missouri.
Post Offices and Mailboxes in Missouri
Where to buy postage stamps in St. Clair County, MO
Now you can print postage immediately using your home printer. Avoid trips to the Post Office. Print USPS postage online with Stamps.com. Get a 4 week trial if you Start Now.