An archaeological site is a place (or group of physical sites) in which evidence of past activity is preserved (either prehistoric or historic or contemporary), and which has been, or may be, investigated using the discipline of archaeology and represents a part of the archaeological record.

Beyond this, the definition and geographical extent of a 'site' can vary widely, depending on the period studied and the theoretical approach of the archaeologist.

It is almost invariably difficult to delimit a site. It is sometimes taken to indicate a settlement of some sort although the archaeologist must also define the limits of human activity around the settlement. Any episode of deposition such as a hoard or burial can form a site as well. Development-led archaeology undertaken as cultural resources management has the disadvantage (or the benefit) of having its sites defined by the limits of the intended development. Even in this case however, in describing and interpreting the site, the archaeologist will have to look outside the boundaries of the building site.