Brushy Creek State Preserve is located in Brushy Creek Recreation Area, a 6,500-acre public area in Webster County located twenty miles southeast of Fort Dodge. During environmental studies conducted as part of a controversial proposal to construct a 1,000-acre recreational lake, a portion of the area was discovered to contain significant geological exposures, archaeological sites, and habitat for the woodland vole, a state-threatened species. In 1988, a 260-acre portion of the recreation area was dedicated as a geological, archaeological, and biological state preserve. A 700-acre lake was later completed upstream from the preserve. Geologically, the scenic Brushy Creek valley, located within the Des Moines Lobe landform region, contains a remarkable record of 11,000 years of history in its alluvial terraces, benches, and apronlike fan deposits. These features display the effects of glacial melting from the Des Moines Lobe as well as the rapid deepening of the nearby Des Moines River valley. In addition, erosion by Brushy Creek has revealed stratigraphic deposits of a pre–Des Moines Lobe landscape. This geologic record, seen nowhere else in northern Iowa, provides important insights into the evolution of the Iowan Erosion Surface. Fossil wood and plant materials found here are dated at 37,000 years and indicate the presence of a spruce forest similar to the Canadian boreal forest of today
