October 2, 2012
HBO announced today that Boardwalk Empire has been renewed for a fourth season. The Emmy Award-winning drama, which chronicles the life of "Nucky" Thompson during 1920s prohibition in Atlantic City, only recently began its third season on September 16, 2012.
“Terry Winter, Martin Scorsese and the rest of their outstanding team continue to produce a stunning show that never fails to surprise and entertain,” said the network's president of programming, Michael Lombardo. “We are excited to bring this unique series back for a fourth season.”
No time frame has been announced for the show's fourth season at the time of this writing.
UPDATE: Season 4 of Boardwalk Empire will premiere on Sunday, September 8, 2013.
(Source: TV by the Numbers)