In response to the global threat of invasive alien species, there has been a proliferation of volunteer-based monitoring programs. The valuable data sets collected through these programs facilitate large-scale, baseline population monitoring. The Invasive Plant Atlas of New England, created in 2001, was the first such regional database and is the only one in which both presence and true absence data have been collected. Building on the success of volunteer atlas projects for other taxa, the Web-based network uses trained volunteers, along with experts, to collect distribution data and detailed environmental information. The incorporation of true absence data allows for the building of robust statistical models, which contributes significantly to the invasive species literature. This collaborative database allows citizen science data to be used by the general public and as a data source for researchers and policymakers. As a template for other invasive plant projects, we highlight the need for more collaborative efforts in invasion ecology.