Jordan lives in her aunt's apartment in Manhattan. The Plaza Hotel was where Jordan, Nick, Daisy, Gatsby, and Tom rented a room on that hot, summer day to get away from the heat.
Jordan Baker is one of the three main female characters in F. Scott Fitzgerald's seminal novel The Great Gatsby. In Chapter Three of the novel, Jordan attends the party at Gatsby's to which Nick has been invited. As he stands idly, Nick sees Jordan "looking with contemptuous interest" down into the garden. Nick calls to her and she holds his hand "impersonally." They stroll around for a while, then enter Gatsby's house where Jordan is invited to speak with him. While she is gone, Nick asks for his hat. The library door opens and Jordan and Gatsby come out together. Jordan's party are calling to her, but she lingers long enough to shake Nick's hand. She tells Nick to come and see her; she is in the phone book under the name of Mrs. Sigourney Howard, who is her aunt. "She was hurrying off as she talked--her brown hand waved a jaunty salute as she melted into her party at the door." When Jordan says "the phone book," she implies the New York phone book, most likely Manhattan where the wealthy live.
Jordan herself makes it somewhat clear where she could possibly be living. She tells Nick, in chapter three, after her hour long meeting with Jay Gatsby in the library:
“Please come and see me. . . . Phone book . . . Under the name of Mrs. Sigourney Howard . . . My aunt . . . ”
Nick also recounts their meeting in the tea-garden at the Plaza Hotel which suggests that she lives close by. Because most of their meetings occur in and around New York, the address that Nick has to find under her aunt's name is, more than likely, one in Manhattan. It is easy to assume that Jordan should live in a wealthier part of the city, in a place central to her general comings-and-goings. She hobnobs with the wealthy and, therefore, has to subscribe to the accepted style and living conditions of those she associates with.
One cannot help but suspect that Jordan is a sponger - one who lives off the generosity of others. This is supported by the fact that she does not have her own apartment. We do not know whether she pays any rental but can assume that her aunt should be of the means to provide rent free accommodation to her famous niece. Furthermore, when Nick meets her for the first time, she is visiting at Daisy and Tom Buchanan's huge mansion. She also seems to be attending parties constantly and has admitted to loving large get-togethers since they are so 'personal.'
Added to that, it does seem somewhat improbable that her career as a professional golfer can generate the type of income she needs to support her lifestyle. However, she is famous and the rich are more than likely happy to welcome her into their company.
It is ironic, then, that Nick should have such a keen interest in her and even to believe that he loves her, since she is the epitome of those he so mercilessly mocks. He constantly ridicules those who attend Jay's parties but obviously sees her differently although he does acknowledge her penchant for lying.