Knife River Indian Villages National Historic Site (KNRI) protects 1758 acres of northern mixed-grass prairie and riparian forests. The Northern Great Plains Inventory & Monitoring Network and Fire Ecology Program surveyed 13 long-term monitoring plots in KNRI in 2012 as part of an effort to better understand the condition of plant communities in the park. We measured plant diversity, vegetative cover, and tree density; looked for the presence of exotic species that are of concern to park management; and evaluated the amount of human and natural disturbance at all plots.