Each local office has different turnaround times on approving files. I do USDA loans all over the country and some offices take 5 business days, some take 6 weeks. The government shutdown stopped USDA in it's tracks, but now that it's over they should begin processing things again. With that being said, it is the government and nothing seems to ever go quickly when it comes to government.
You can ask your lender to request an update from USDA. They probably won't update your specific file, however they will say they are currently viewing applications submitted on X date. If you know the exact date your file was submitted by your lender to USDA then that should give you an idea of when to expect your approval to come through.
Remember Eric, the file cannot generally be submitted to USDA until it has gone through underwriting with your lender and cleared most of the conditions. So if you applied with your lender in mid-september then we're really not talking about a long time here. USDA may not have gotten the file until October.
Hope this helps!