The Terminal Bar is one of my favorite spots in the station, there are lots of well done aspects to it. The huge eye-catching sign in the Great Hall is one of the first things you will notice when you walk into the station. They serve 30 different beers from Colorado, which you can drink in the bar area, inside or outside, or in the Great Hall.
The Cooper Lounge is an upmarket cocktail bar, upstairs on the mezzanine level. In order to get up there you have to check in with the reception desk in the Great Hall, near ACME Burgers and Brats. It has cool views down into the Great Hall, and through the big windows along 17th Street (though you need to stand up to see either!). They serve food from the raw bar at Stoic & Genuine – oysters, shrimp, lobster and caviar.
Union Station Guide 