Determining the Age of GLO-mapped Trail Networks: A GIS Analysis of Northern Iowa

Between 1833 and 1861, the Government Land Office (GLO) mapped almost 11,000 km of trails in Iowa. It is unknown if substantial portions of this GLO-mapped trail system predate the arrival of Euro-Americans; it is possible they were established in prehistory and used into the historical period. This Geographical Information Systems study compares a sample of archaeological sites within 1 km of the GLO trails in northern Iowa with a control sample. It was expected that GLO trails would be more common near Late Prehistoric sites if much of the GLO trail system was established before Euro-American arrival. Analysis indicates a relationship between GLO-mapped trails and Late Prehistoric, early historic Indian, and early historic Euro-American sites. Statistically, the connection between GLO trails and early historic Euro-American sites is by far the strongest; however, biases in the data suggest the association between Late Prehistoric and early historic Indian sites and GLO trails is underestimated.