Choosing the location for a royal tomb was an important responsibility and the Vizier was involved in the selection process. The choice must have been based on several factors, including the quality of the rock stratum, the accessibility and security of the site, and its suitability for the kind of tomb entrance and plan that would be cut. There are several places where tomb cuttings were started and then abandoned. They have not been studied in any detail, although such a study would be valuable to learn more precisely the reasons for choosing a site.
The choice of site location changed over time. Royal tombs in the first half of Dynasty 18 were placed high in the hills or even in cliff faces, often below "waterfalls" where water runs off hillsides above during heavy rains. The reason for this choice may have been that the rock was already fissured here, where water had cut into the cliff, and these fissures made the stone easier to cut. Or perhaps tombs were placed below "waterfalls" so that over time they would be buried beneath debris carried by the floods.
At the end of Dynasty 18 and during the first half of Dynasty 19, tomb entrances were cut closer to the valley floor, at the bottom of low hills in front of the surrounding cliffs. There are exceptions to this, such as a group of tombs from the end of Dynasty 19: KV 13, KV 14 and KV 15 were cut into the base of the cliff near KV 38, the tomb of Thutmes I. By the second half of Dynasty 20, the monumental entrances of royal tombs were cut into the bases of hills on the valley floor.