The town is located north of the Harz mountains, about 123 m above NHN. The nearest mountains reach 181 m above NHN. The largest part of the town is located in the western part of the Bode river valley. This river comes from the Harz mountains and flows into the river Saale, a tributary of the river Elbe. The municipal area of Quedlinburg is . Before the incorporation of the two (previously independent) municipalities of Gernrode and Bad Suderode in January 2014 it was only .