What's open and what's closed on Labor Day? Not everything will be closed during the three-day holiday weekend. While many government offices won't be open, it's a big weekend for retail sales, so many popular stores —including Walmart, Target, and Best Buy —will be open for business on September 4.

Keep in mind, many stores and malls will have special holiday hours. The same goes for restaurants, liquor stores, and supermarkets. And what about the U.S. Post Office, banks, and credit unions? We have the scoop on that, too. Here’s a roundup of what will be (and won't be) open on Labor Day.

Labor Day is a federal holiday so most government employees will have the day off.

That's not the case for people who work at retail stores and restaurants though. It's business as usual for most stores, malls, and dining spots on September 4.

Post Office — open or closed?

There is no mail delivery on Monday and all branch offices will be closed. If you didn't get to the post office to mail a package or check your P.O. Box before your local branch closed on Saturday, you will have to wait until Tuesday, September 5 for doors to open again. UPS and FedEx won't be delivering packages on Monday, either.

The U.S. Postal Service isn't the only federal office that will be closed on Monday. Most courts (state and federal) will be closed on Monday. The DMV (or RMV), the Social Security Administration, IRS offices, and public schools will be closed as well.

Banks and credit unions

The Federal Reserve Bank will be closed on Labor Day.

Most credit unions and banks, including Citibank, Citizens Bank, Chase, TD Bank, and Wells Fargo, will be closed on September 4.

Need cash? Head to an ATM machine. Remember, if you withdraw money out of an ATM that's not in your bank's network you will be charged a fee, generally $1.50 - $4 per transaction.

Stores and malls

Shop 'til you drop this weekend. Most retail stores will be open all weekend, right through the Labor Day holiday. Expect to find sales on everything from clothing, home goods, appliances, and tech gadgets this weekend.

Need a new grill for your Labor Day cookout? Many stores, including Lowe's, Walmart, Target, and Home Depot are offering money-saving Deals on gas and charcoal grills.

Supermarkets will also be open on Monday but it's best to call ahead as many stores will close early for the holiday. Of note, Costco will be closed on September 4, so stock up on food for your cookout before the warehouse store closes on Sunday.

Many restaurants will be open

Don't feel like cooking for a crowd on Labor Day? Most popular chain restaurants including TGI Fridays, Olive Garden, Cracker Barrel, and Applebee’s will be open throughout the three-day holiday weekend. Call ahead for hours.