Although the Chicago region is highly urbanized, it contains remnant natural areas that support rare species. Land managers use rare species data in management planning, but they are often unable to collect this data on a scale at which it is needed. Plants of Concern (POC) was founded to address this need, and in 2016, POC completed its sixteenth year of operation. Since this time, POC has trained and engaged 849 citizen scientists who have contributed over 29,000 hours in the field and office. The program has monitored 283 endangered, threatened, and rare species at over 300 sites in 1,315 populations throughout the Chicago Wilderness region. A state-wide monitoring program, modeled after POC, was started in Wisconsin in 2015, but POC continues to coordinate monitoring in northeastern Illinois and northwestern Indiana. A strongly collaborative regional effort, POC has worked with over 100 public and private landowners (Appendix 1). For their participation, these landowners receive critical data for use in management planning. In 2016, grant funding supported a special focus on monitoring at Midewin National Tallgrass Prairie (for the 14th year), Openlands Lakeshore Preserve, and the Cook County Forest Preserves, and along the north shore of Lake Michigan. A separately funded project is resulting in a rapid vegetation assessment method for the Chicago Park District. Analyses of POC’s long-term dataset are yielding critical information on rare species’ population trends in relation to management activities on a region-wide basis. POC has become a recognized model citizen science program, and staff have given talks at local, national, and international conferences (Goad, Vitt, Miller, Steffen, Rosenbaum, Yates, interns, and collaborators).