It was designated a National Historic Landmark in 1977 because it yielded dense archaeological remains as well as evidence for what is quite possibly the oldest structure in North America.

The major occupations at Thunderbird site are known to date to the Late Pleistocene-Early Holocene epochs and include Clovis and later projectile points forms, as well as an array of other tools and manufacturing debris.

[5] Thunderbird is considered a part of the Flint Run Complex and consists of a group of sites located in and around a jasper quarry.

[7] Because of its stratified deposits, Thunderbird is one of the sites used to develop a sequence of Paleo-Indian and Early Archaic assemblages in Eastern North America.

This contradicts earlier views that Paleoindian peoples lived in small groupings except for the occasional large gathering for a few weeks at a time to maintain kinship networks as well as share food source knowledge.