(CNN) In 1983, President Ronald Reagan officially declared Martin Luther King Jr. Day a national holiday , but it wasn't until 1986 that it was celebrated that way. Since then, the holiday has allowed many Americans the day off to remember the legacy of the prominent civil rights leader. But it also makes it confusing to know what stores, services and buildings are open or closed.

Well, let this be your guide before you head out the door. Here's what's open and closed on January 20, 2020.

Post office is closed

Minus a few select locations, US Postal Service offices will be closed. There will be no mail delivery to homes and businesses except for Priority Mail Express, according to USPS. If you need something delivered, UPS is open. FedEx is operating, but with modified service for FedEx Express and FedEx SmartPost.

Most banks are closed

A majority of US banks are closed because they follow the holiday schedule of the Federal Reserve System, which is the nation's central bank. That includes most Bank of America, Chase and Wells Fargo bank locations. But that shouldn't stop you from being able to take out some quick cash as ATMs and online banking will be operating. Also closed are the New York Stock Exchange and Nasdaq.

What about the DMV?

Most DMV offices will be closed, as they are government agencies. Same goes for courts and other nonessential government buildings.

Most retail and grocery stores, restaurants are open

You'll have plenty of options to choose from if you plan on using the day to do some shopping or eating out, as most big restaurant chains, retail stores and grocery stores will be open. That includes Costco, Walmart, Kroger, Starbucks and Chick-fil-A. But check with your local retailers, as hours may differ by location.