The Wife of Bath's Prologue is technically a part of the frame story of The Canterbury Tales, meaning that it's a part of the action that occurs among the characters, between the tales that they tell. This means that the Wife's Prologue takes place on the pilgrimage between London and Canterbury. Because the Wife narrates numerous flashbacks, however, the setting of her Prologue actually shifts in time and place from the pilgrimage to the sites and times of the Wife's previous marriages.
The most vivid flashback we get, of the episodes leading up to and during her marriage to her fifth husband, sets the action in the medieval town where the Wife lived with him. From the Wife's point of view, this town is an immensely social place. There, the Wife can walk "Fro hous to hous, to here sondry talis" (553), chat with her "gossip" and niece, who seem to form the core of her social group, and make "visitaciouns / To vigilies and to processiouns, / To preching eek and to thise pilgrimages, / To pleyes of miracles, and mariages," the better to see and be seen (561-564). To the Wife this social life is immensely important, for, as she says, "What wiste I wher my grace / Was shapen for to be, or in what place?" (559-560). In other words, since the Wife never knows from what person her next opportunity for advancement will come, she tries to meet as many people as possible – she's the ultimate social networker. From her, then, we get a unique perspective on the social life of a medieval town, and the opportunities for amusement, social intercourse, and advancement it might offer a woman like the Wife of Bath.