In the opening chapter, we learn when we meet Jenny Waynest that Barbara Hambly's fantasy novel Dragonsbane is set in a region called Winterlands. Based on Jenny's description, Winterlands is apparently a very dangerous, crime-ridden place, as we learn when she states that, while riding through the "ruins of the old town," she sensed the presence of bandits, and she was not sure if it was her magic as a witch that allowed her to sense them "or simply woodcraftiness and instinct for the presence of danger that anyone developed who had survived adulthood in the Winterlands."
By the time we meet Gareth of Magloshaldon, who thinks he is coming to Jenny's rescue, we also learn that within the Winterlands lies the village of Alyn Hold, as we see when Gareth tells Jenny he is looking for "Lord Aversin the Dragonsbane, Thane of Alyn Hold and Lord of Wyr." The name Alyn Hold is the name of one of the villages Lord Aversin rules over. By Chapter 3, we learn that Wyr is the name of the province in which Winterlands and the village of Alyn Hold lie. Jenny, Lord Aversin, and Gareth are all setting out to fight a dragon in the province of Bel.
While the story is set in a completely fictional land, due to references to past kings, dragons, and horses, we can also understand it is set in a time period like the Middle Ages.