As part of the National Park Service's effort to "improve park management through greater reliance on scientific knowledge," a primary role of the Inventory and Monitoring (I&M) Program is to collect, organize, and make available natural resource data. A list of species known to occur in NPS units is considered a basic inventory need (see: http: //science.nature.nps.gov/im/inventory/index.cfm). The I&M Program's Heartland Network (HTLN) recently completed inventories of vertebrate species and vascular plants at Effigy Mounds National Monument (EFMO). In doing so, all existing data were cataloged, targeted field investigations were conducted, and species lists were certified by taxonomic experts. The primary goal of these efforts was to document at least 90% of the vertebrate and vascular plant species believed to occur in the park. This report provides a summary of results.