From the New York Times:

Among the signs that the Clinton presidential kabuki is ending — that Senator Hillary Rodham Clinton will, in fact, announce her campaign for the White House soon — is a decision, Democrats close to her say, that she plans to base her campaign headquarters in or around Washington instead of in White Plains or New York, which had been under consideration.
Running from a base in Washington would make the most practical and financial sense, Clinton advisers say, and they note that she would have satellite offices in New York and elsewhere. Still, a few advisers and supporters are concerned about the decision, saying it could reinforce her image as a Washington insider (if it is possible for that to be any more of an issue) and increase the possibility of leaks to the press corps (as if, ditto).
“One group thinks headquarters should be wherever is easiest for her, and another group is worried about public perception, since Washington is an unpopular place,” said an adviser who has been involved in the discussions and who insisted on anonymity. “The thing is voters in the end won’t really care where she runs from.”