This dataset contains high accuracy (< 10 cm error) GNSS ground truth measurements of the invasive reed Phragmites australis subsp. australis within Îles-de-Boucherville National Park (Quebec, Canada). The park, which has extensive stands of P. australis throughout the area, is one of the five study sites for the Canadian Biodiversity Airborne Observatory (CABO). The data were originally collected to serve as training and validation data for airborne hyperspectral imagery acquired in 2019 to assist with the detection and mapping of P. australis within the park, as no previous ground truth data had been collected at this site with such accurate measurements. In total, 320 ground truth points were collected, representing 158 locations where P. australis was present and 162 locations where it was absent. Auxiliary data includes detailed field notes and field photographs that provide context for each point, as well as a shapefile (.shp) containing all 320 points.