How Do Archeologists Find Sites?

Above-ground, noninvasive techniques and minimally-disturbing, invasive techniques help archeologists to locate sites. Oftentimes, these investigative techniques yield enough information to make full-scale excavation unnecessary.

Only NPS employees or permitted individuals are legally authorized to do archeological studies on NPS lands. For more information, read about the Archaeological Resources Protection Act of 1979.

Above-ground, Noninvasive Techniques

Archeologists don't have to disturb the ground at all to find archeological sites.

• Predictive models assume patterns of human settlement within particular periods and environments. They draw from known site locations and analogies with ethnographically-known societies.
• Archival research draws from text-based, historical sources. These sources include government documents, maps, journals, photographs, and tax records. Fieldwork may confirm or conflict with archival sources.
• Oral histories are information passed by word of mouth. They may be one person's memories, or knowledge or traditions passed through generations.
• Surface inspection (also known as “reconnaissance,” “above-ground survey,” or “walkover)" is when archeologists walk in a systematic way over an area. They record and collect information from the surface only.
• Geophysical prospecting or remote sensing identifies archeological features buried below ground. Its techiques include aerial photography, aerial infrared photography, imaging radar, electrical resistivity, electromagnetic surveys (also known as metal detecting), ground penetrating radar (GPR), magnetic prospecting, and other technologies.
• Previous excavations record information about the location of similar or related sites. Archeologists may consult reports or other archeologists to decide where to look.

Minimally-disturbing, Invasive Techniques

Some ground disturbance may be necessary to confirm archeologists' suspicions.

• Archeological surveys (also known as "site testing" or "evaluation") identify archeological resources in an area and address the scope of a site or set of sites.
• Sampling investigates part of an area in a systematic way. Archeologists base the sampling research design on existing knowledge, mathematical probabilty, or a combination of the two.