We’re not even a month into 2012, and a new slew of bars and restaurants is already arriving in the Washington area. We’ve already covered the openings of Society Fair, Boxcar, Irish Whiskey Public House and Fuel; today we’ll check out two established D.C. bars that are expanding operations: St. Arnold’s Mussel Bar has opened a location in Cleveland Park, and Glover Park’s Town Hall has doubled in size since moving into the former Blue Ridge space on Wisconsin Avenue.

St. Arnold’s Mussel Bar

St. Arnold’s is a cozy, basement-level Belgian beer bar and mussels restaurant hidden away on Jefferson Place NW, a quiet little sidestreet just steps away from the bustle of Dupont Circle and Connecticut Avenue. While it offers a better-than-average draft lineup and huge, delicious bowls of classic moules-frites, part of its allure has been its out-of-the-way location.

The bar’s second location is anything but out-of-the-way: right in the middle of Cleveland Park at Connecticut and Ordway in the old Sabores space. St. Arnold’s Mussel Bar looks more like a solarium than a beer bar, with glass “walls” that roll up in good weather, a small bar and a sea of blonde wood tables. The mussels are every bit as good as at the original — sizzling metal pots filled with bivalves floating in a rich, creamy broth of herbs and meat. (The L’Alsacienne has long strips of bacon and chunks of potatoes and leeks hiding in the caper-and-wine sauce.) If only the wimpy frites were a match for the moules.

A solid if unspectacular list of taps includes such famous Belgian names as Palm, Duvel, Leffe and De Koninck, and there’s also an interesting Belgo-German bottle selection.

Prices are still worth warning about: The mussels are a flat $18 per pot, though you could definitely share them for a lighter meal, especially if you employ the provided French bread to soak up the sauce.

Meanwhile, in a bit of European Union togetherness, the building’s basement level — previously home to bars called the Uptown Tavern and the Park Bench Pub — has become a bar called London Underground. (Yes, it uses London’s famous subway logo. How did you know?) The Anglo-Irish theme comes from Fuller’s and Newcastle beers on tap, framed Radiohead and Coldplay albums above the bar, and walls stenciled with band logos, including U2, Blur and Pink Floyd. A dart lane and pool table provide entertainment; watch out for a weekly pub quiz.

Town Hall

Glover Park’s popular Town Hall restaurant and bar has moved one block north on Wisconsin Avenue, taking over the two-level building that housed Blue Ridge. The public got its first look at the space at a sold-out New Year’s Eve party, but the new Town Hall is now open on a daily basis. It’s an impressive space. The revamped interior includes a huge bar, with an adjacent window-filled nook, and a dining room that’s far more spacious than its old location. (Owner Paul Holder estimates that the capacity has doubled.) Upstairs includes multiple rooms with couches, a pool table, two bars and a comfortable deck overlooking a rear courtyard.

That courtyard, which includes a fire pit, should be ready to go in time for March Madness and St. Patrick’s Day, Holder says, and he’s planning to offer weekend brunch al fresco.

In the meantime, the best time to visit Town Hall may not be a weekend — the bar was at capacity with a one-in, one-out policy last Saturday night. Instead, head over for the “Locals and Lights” happy hour from 5 to 7 on weekdays. Beers by Delmarva brewers (Dogfish Head, Starr Hill, Flying Dog and DC Brau) cost $3 instead of the usual $5 to $6.50, and Miller Lite and Coors Light drafts are also $3. Selected wines by the glass cost $4.