Located near Lewis Canyon about twenty miles south of the South Platte River in northeast Colorado, the Donovan Archaeological Site is a Late Prehistoric bison-processing area with evidence of multiple Upper Republican occupations between about 1000 and 1300 CE. The site was later used by Dismal River hunting parties around 1625–1750 CE and possibly by Cheyenne or Arapaho groups even more recently.
The Donovan Site was discovered in the early 1980s, when Lloyd Hobbes found bone and stone artifacts protruding from the bank of an arroyo in Lewis Canyon after heavy thunderstorms. Named for the landowner, the site was excavated from 1982 to 1985 by the Denver and Sterling chapters of the Colorado Archaeological Society. Working on weekends each summer and fall, the amateur teams excavated more than twenty-five square meters and recorded thousands of stone artifacts and pottery sherds along with huge amounts of bison bone. After the amateur teams ceased their excavations in 1985, the portions of the site near the bank of the arroyo experienced heavy looting.
By 1990, archaeologist Mike Toft of Sterling convinced Charles Reher of the University of Wyoming to make the site a focus of the university’s High Plains Archaeology Project. In 1992 the project started its work at the Donovan Site, with the goal of dating and documenting the extent of the deposits in an attempt to place the site in the broader context of high plains Upper Republican research. Over the next fifteen years, the High Plains Archaeology Project conducted eight field seasons of about thirty workdays each, generating dozens of conference papers and student reports.
The excavations showed that a variety of activities occurred at the Donovan Site, but the primary focus was butchering and processing bison. The site contained many small bone fragments, suggesting that the animals were killed elsewhere before the bones were transported to the site for processing. In addition, most bones at the site were from adult bison, indicating small-scale hunts rather than indiscriminate mass kills.
The Donovan Site and other high plains Upper Republican sites like it have led archaeologists to speculate about their relationship to the more substantial Upper Republican settlements found on the central plains. Early theories proposed that the high plains sites represented hunting parties from the central plains; later, scholars hypothesized that a local, perhaps unrelated, hunter-gatherer population used the sites. More recently, Laura Scheiber and Charles Reher have suggested that high plains Upper Republican sites could represent seasonal hunting or scouting rounds that eventually resulted in the permanent migration of some Upper Republican groups from the central plains to the high plains.
In 2009 Michael Page completed a comprehensive reanalysis of high plains sites previously classified as Upper Republican and showed that the high plains were actually occupied by a variety of Central Plains tradition peoples, especially the Itskari variant. Although Page noted that the Donovan Site was Upper Republican rather than Itskari, his work suggested a new framework for looking at high plains sites dating to the early 1000s CE. Itskari people probably traveled regularly to the high plains to procure stone and hunt bison. Upper Republican people used the high plains less intensively, probably when periodic droughts forced them away from the central plains.